How to find clues(tracing &hunting)

搜索剪枝常见方法与技巧关键字搜索方法,剪枝摘要搜索是计算机解题中常用的方法，它实质上是枚举法的应用。

由于它相当于枚举法，所以其效率是相当地的。

因此，为了提高搜索的效率，人们想出了很多剪枝的方法，如分枝定界，启发式搜索等等。

在竞赛中，我们不仅要熟练掌握这些方法，而且要因地制宜地运用一些技巧，以提高搜索的效率。

正文搜索的效率是很低的，即使剪枝再好，也无法弥补其在时间复杂度上的缺陷。

因此，在解题中，除非其他任何方法都行不通，才可采用搜索。

既然采用了搜索，剪枝就显得十分的必要，即使就简简单单的设一个槛值，或多加一两条判断，就可对搜索的效率产生惊人的影响。

例如Ｎ后问题，假如放完皇后再判断，则仅仅只算到７，就开始有停顿，到了８就已经超过了２０秒，而如果边放边判断，就算到了１０，也没有停顿的感觉。

所以，用搜索就一定要剪枝。

剪枝至少有两方面，一是从方法上剪枝，如采用分枝定界，启发式搜索等，适用范围比较广；二是使用一些小技巧，这类方法适用性虽不如第一类，有时甚至只能适用一道题，但也十分有效，并且几乎每道题都存在一些这样那样的剪枝技巧，只是每题有所不同而已。

问题一：(最短编号序列)表A和表B各含k(k<=20)个元素，元素编号从1到k。

两个表中的每个元素都是由0和1组成的字符串。

（不是空格）字符串的长度<=20。

例如下表的A和B两个表，每个表都含3个元素（k=3）。

表A 表B对于表A和表B，存在一个元素编号的序列2113，分别用表A中的字符串和表Array对表A和表B，具有上述性质的元素编号序列称之为S(AB)。

对于上例S(AB)=2113。

编写程序：从文件中读入表A和表B的各个元素，寻找一个长度最短的具有上述性质的元素编号序列S(AB)。

（若找不到长度<=100的编号序列，则输出“No Answer”。

对于这道题，因为表Ａ和表Ｂ不确定，所以不可能找到一种数学的方法。

因为所求的是最优解，而深度优先搜索很容易进入一条死胡同而浪费时间，所以必须采用广度优先搜索的方法。

Historical linguisticsThere are over 5,000 distinct human languages in the world. One very basic question is how did they all get there? Historical linguistics is the branch of linguistics that focuses on the interconnections between different languages in the world and/or their historical development. Historical linguists investigate how languages evolve and change through time, how multiple "offspring" languages can arise from one past "parent" language, and how cultural contact between speakers of different languages can influence language development and evolution. We all are aware that English has changed over time. None of us would be able to understand Old English as it was spoken many centuries ago. We also know of words such as "astronaut" that our great grandparents would not have known about.A basic assumption in historical linguistics is that languages are constantly changing. Rather than assuming that languages are static, non-changing "things," we need to think about them as one of the most dynamic areas of culture.The purpose of this section is to point out some of the historical relationships that are known between different languages of the world and to discuss the dynamic aspects of language in generalthat are ultimately responsible for these historical relationships. We also want to explore how languages can change and what types of mechanisms are involved in that change process.So how do languages change?The Reconstruction of Historical Relations:CognatesTo understand how linguists have been able to reconstruct relationships between different languages in the world we need to know something of cognates. Cognates are vocabulary words from two or more languages which sound similar and refer to the same thing. Cognates serve as preliminary clues that languages are related to one another since the languages share strong similarities in the form and meaning of certain vocabulary. Each column below contains words from one language. The words in each row refer to the same thing (such as "hand") for each language. Move your mouse to each button and click on it to listen to each word in the four languages (move from left to right on each row).1. Moving from left to right on each row, which words sound like cognates of one another (i.e., which words sound very similar) and which ones are distinct?2. Based on this very short list of words can you decide which languages seem to be more closely related to one another?3. Can you determine if there is/are "mystery" languages here - things that don't fit?Word BorrowingNow you can better appreciate why linguists use cognates to analyze the historical relationship between languages. Cognates can be used as modern "clues" to the past and the potential historical relationships of two or more languages. If two languages share a great number of cognates, it is often good evidence that the languages developed from a common ancestral language. For example, European scholars have long known of the importance of Latin as the historical "root" language for the so-called "Romance Languages" (e.g., Spanish, Portuguese, French, Italian, etc.). The Romance languages share a great number of cognates owing to their common Latin origin.(Note: An important note of caution, however, is that any analysis of cognates should use basic words that we would expect to find in all languages historically; doing so cuts down on the risk that a particular word has been borrowed into many different languages. (For example, one wonders how many languages have borrowed the word "Internet" to explain this new technology!!) Words more basic to a vocabulary of a particular people (e.g., hand, mother, sky, etc.), are less likely to be borrowed from outside languages. As a result, if two languages share a large number of cognates, the similarities are more likely to be a product of the past historical relationship between the languages.)Reconstructing CognatesThe meanings of these words are not always exactly the same as the column heading, but clearly derive from it. For example, mitelhen in Chukchi means "expert," mit in Korean is "to believe," and mede in Mongol means "to know." A broad and relative interpretation of word meaning is in itself an important feature of how linguists such as Joseph Greenberg probe farther back in time tracing language evolution. Loans from other languages and coincidences may intervene, but there are a number of good reasonswhy these sources of error do not seriously interfere with conclusions about how languages relate. The list of cognate words is limited to those least susceptible to change over time and therefore unlikely to be loaned from other languages. It is highly improbable that there should be multiple coincidences for numerous words drawn from a large number of languages.If we take languages closely related to those listed in the table, the similarities increase. For example, the first person singular pronoun in ancient Japanese is mi, older brother is also aka in Turkish, the Japanese of Ryukyu island, and in many of the Ainu languages. The Ainu once inhabited the whole Japanese archipelago, but today only live on Hokkaido and farther north in the Sakhalin islands. They are physically distinctive from Japanese as well as speaking a different language.Language MappingLanguage families can be traced geographically.The Indo-European Language FamilyNorth American Language MapThis map is clickable. Click on any of the colors to learn aboutthe languages in that area.The primary issue is why and how do languages change? In the next section, we will explore some of the mechanisms that lead to change. First let'slook at small differences....Dialects - Small DifferencesIf multiple languages can be shown to all come from the same common root language, which we assumes happens, what is the historical process that ultimately leads to their separation into different languages?One clue to this process can be seen in dialects. A dialect can be defined as a geographical or social subdivision of a language that differs systematically from other such subdivisions of the same language in its vocabulary, grammar, and phonology.We commonly know that we are in the presence of a person speaking a different dialect of English than our own when that person"sounds funny" or uses "strange words" to describe something. Even though we can understand what the person is saying we realize that their dialect is different from our own.Exercise"dialects of English can you define?< of and between the groups? more) (or two differences dialectical significant in resulted isolation communicative this separated were people where examples historical some think you Can>Historical LinguisticsThe importance accorded to historical linguistics has diminished considerably during the 20th century. In the 19th century and the beginning of the 20th, historical linguistics was considered by many - or even most - linguists as the most important branch of linguistics, what linguistics was really about. It is no doubt a good thing that other aspects of linguistic sciences have been able to flourish since then, but in my view the historical aspects of language are important, and linguists would, on the whole, benefit from a better understanding of the historical processes that languages are constantly subject to, and that have shaped the languages as we are able to study them today.One of the most significant results in the history of linguistic sciences was the establishing and perfection of the comparative method in historical linguistics (see below) and, in the process, the establishing of the genetic relationship of the members of the Indo-European language family and of many other language families. The reference work Ethnologue: Languages of the World has a list of language families with further links; for instance, there is a link to a list of Indo-European languages spoken today, and some extinct ones.Historical linguistics can be divided into several sub-disciplines:etymology- the study of the origins and historical development of wordsdialectology - the study of dialects (varieties of a language that are characteristic of particular groups, determined by geographical, social, religious and other factors); in the context of historical linguistics, how dialects develop over timephonology - the study of the sound systems of a language or group of languages; in the context of historical linguistics, how sound systems change over timemorphology - the study of the formal means of expression in a language; in the context of historical linguistics, how the formal means of expression change over time; for instance, languages with complex inflectional systems tend to be subject to a simplification processsyntax - in the context of historical linguistics, how characteristics of sentence structure change over timeThe phonological, morphological and syntactic (and other) aspects of language change are not separate processes but are closely interlinked. For instance, as a result of simplifications in the sound system it may be necessary to restructure the inflectional system; this in turn may affect the syntactic structure. Influences in the opposite direction can also occur, although they are probably less frequent.The comparative method in historical linguisticsThis was largely developed during the nineteenth century. The essence of the method consists in observing systematic correspondences of sounds (or, in the case of extinct languages, the graphemic representations of sounds, usually letters of some alphabet) between significant numbers of words with related meaning in two or more different languages. When such correspondences occur in sufficient numbers, they cannot be due to chance and must mean that the differences in phonological shape must be the result of different phonetic developments from the same or similar word forms, i.e. the two languages must have developed from one and the same language. With this method it has been possible to establish the 'genetic' relationships between hundreds of languages belonging to the same language family, for instance the Indo-European language family. Similarly, the genetic relationships between the members of other large language families like the Semitic, Finno-Ugric and Bantu have been established with a great degree of certainty.。

科学精神收集鹅卵石英语作文The Scientific Spirit Collecting PebblesThe world we live in is a vast and wondrous place, filled with mysteries waiting to be unraveled. As human beings, we possess a deep-rooted curiosity that drives us to explore and understand the intricacies of our surroundings. This innate desire to seek knowledge and make sense of the unknown is what we call the scientific spirit. It is a mindset that embraces the pursuit of truth, the questioning of assumptions, and the relentless pursuit of understanding.One of the most captivating manifestations of this scientific spirit is the act of collecting pebbles. On the surface, it may seem like a simple and mundane task, but when viewed through the lens of scientific inquiry, it becomes a fascinating journey of discovery. Each pebble, with its unique shape, color, and texture, holds the potential to reveal the secrets of our planet's history and the forces that have shaped it over time.As a scientist, the act of collecting pebbles becomes a meticulous and methodical process. It begins with the careful observation of the surroundings, scanning the ground for the most intriguingspecimens. The collector's eye is trained to identify patterns, textures, and subtle variations that might otherwise go unnoticed by the untrained observer. Each pebble is then carefully examined, its surface scrutinized for any clues that might shed light on its origin and composition.The true magic of pebble collecting, however, lies in the stories that these humble stones can tell. By studying the geological features of a pebble, a skilled scientist can uncover a wealth of information about the Earth's past. The color and texture of a pebble may reveal the type of rock it was formed from, while its shape and smoothness can provide insights into the erosional forces that have acted upon it over time.For example, a rounded pebble found on a beach may have been shaped by the relentless pounding of waves, while a more angular pebble from a mountainside may have been fractured by the freeze-thaw cycles of the elements. By piecing together these clues, the collector can begin to reconstruct the journey of each pebble, tracing its path through the vast and dynamic landscapes of our planet.But the scientific spirit of pebble collecting goes beyond mere observation and deduction. It also involves the desire to share and communicate these findings with others, to contribute to the collective understanding of our world. The collector may carefullycatalog and document their findings, creating detailed records that can be used by researchers and educators to further our knowledge of geology, geography, and the natural world.In this way, the act of pebble collecting becomes a testament to the power of the scientific spirit – the unwavering drive to explore, to understand, and to share knowledge. It is a pursuit that transcends the boundaries of age, gender, or background, uniting people from all walks of life in a common quest for understanding.As we delve deeper into the wonders of the natural world, the scientific spirit of pebble collecting serves as a reminder of the endless possibilities that await us. Each pebble, no matter how small or unassuming, holds the potential to unlock new insights and inspire further exploration. It is a testament to the enduring human desire to understand the world around us, to uncover its secrets, and to share our discoveries with others.In the end, the scientific spirit of pebble collecting is not just about the stones themselves, but about the journey of discovery that they represent. It is a testament to the power of curiosity, the value of careful observation, and the joy of uncovering the hidden stories that lie beneath the surface of our world. And as we continue to collect and study these humble pebbles, we are reminded of the boundlesspotential of the human mind to explore, to understand, and to create a better future for all.。

追寻你的足迹小标题作文英文回答：Title: Tracing Your Footsteps.As I embark on the journey of tracing your footsteps, I am filled with anticipation and excitement. It is like a treasure hunt, seeking clues and unraveling the stories behind each step you have taken.I start by visiting the places you have lived. From the cozy neighborhood in the suburbs to the bustling city streets, each location holds memories and experiences that have shaped you. For instance, I imagine walking down the streets of your childhood home, where you played with friends and learned valuable life lessons. Or perhaps I could stroll through the vibrant markets of the city where you discovered your love for exotic cuisine.Next, I delve into the educational institutions youattended. Whether it is a prestigious university or a local community college, these places have played a significant role in your personal and intellectual growth. I can imagine sitting in a lecture hall, absorbing knowledge from esteemed professors, or participating in lively discussions with classmates who have become lifelong friends.Furthermore, I explore the workplaces you have been a part of. From the corporate office with its suits and ties to the creative studio filled with paint and brushes, each work environment has shaped your professional journey. I can picture you collaborating with colleagues, brainstorming ideas, and overcoming challenges to achieve success.In addition to physical locations, I also trace your footsteps through the hobbies and activities you enjoy. Whether it is playing a musical instrument, practicing a sport, or engaging in volunteer work, these pursuits reveal your passions and interests. For example, I can imagine you strumming a guitar, lost in the music as you express your emotions through melody and lyrics. Or perhaps I could joinyou on a volunteer trip, witnessing the joy and fulfillment you experience from helping others.As I trace your footsteps, I am not only discovering the places you have been but also the person you have become. Each step represents a choice, a decision that has shaped your life. It is through these experiences that you have grown, learned, and evolved into the person you are today.中文回答：标题，追寻你的足迹。

英文作文我爱猜字谜全文共2篇示例，仅供读者参考英文作文我爱猜字谜1:Title: The Joy of Solving Riddles: A Journey Through the World of WordplayWordplay has been an integral part of human culture for centuries, transcending boundaries of language and geography. Among the myriad forms of wordplay, one stands out for its charm, creativity, and intellectual challenge: the art of solving riddles. In this essay, we embark on a journey through the captivating realm of riddles, exploring their history, significance, and the sheer delight they bring to both young and old.Introduction: Unveiling the MysteryRiddles, often defined as enigmatic puzzles that require ingenuity and lateral thinking to solve, have fascinated people across cultures for generations. From ancient civilizations to modern societies, the allure of unraveling a cleverly craftedriddle continues to captivate minds and spark joyous moments of revelation. In the realm of English literature, riddles have left an indelible mark, finding their way into the works of esteemed writers such as William Shakespeare and J.R.R. Tolkien.The Art of Wordplay: Crafting and Deciphering RiddlesAt the heart of every riddle lies the artful manipulation of language—a delicate dance of words designed to conceal and reveal simultaneously. Whether in the form of witty rhymes, cunning wordplay, or cryptic clues, riddles challenge our cognitive faculties and invite us to engage in a playful exchange of wit and wisdom. Consider the timeless riddle: "I speak without a mouth and hear without ears. I have no body, but I come alive with wind." The answer, of course, is an echo —a prime example of how riddles harness the power of language to evoke curiosity and spark imagination.Historical Perspectives: Tracing the Origins of RiddlesThe origins of riddles can be traced back to ancientcivilizations, where they served as both entertainment and educational tools. In ancient Greece, riddle contests known as "rhapsode" were held during festivals, showcasing the prowess of poets and thinkers in crafting and solving intricate puzzles. Similarly, the Anglo-Saxon tradition boasts of the Exeter Book, a manuscript dating back to the 10th century, containing a rich collection of riddles that offer insights into the cultural and intellectual milieu of the time.The Psychological Appeal: Engaging the MindWhat is it about riddles that captivates the human mind? Psychologists suggest that the allure of solving riddles lies in their ability to engage multiple cognitive processes simultaneously. From pattern recognition and inference to deductive reasoning and creative problem-solving, tackling a riddle stimulates various regions of the brain, fostering cognitive flexibility and mental agility. Moreover, the element of surprise and the satisfaction of uncovering hidden truths add a layer of emotional reward to the intellectual challenge, making the experience doubly gratifying.Educational Significance: Fostering Critical Thinking and Language SkillsBeyond mere entertainment, riddles play a valuable role in education, particularly in the development of critical thinking and language skills. By encouraging students to think outside the box and approach problems from different perspectives, riddles cultivate a spirit of inquiry and innovation. Moreover, the linguistic complexity inherent in many riddles promotes vocabulary enrichment, linguistic creativity, and a deeper appreciation for the nuances of language. In classrooms around the world, teachers leverage the inherent appeal of riddles to make learning engaging and memorable.The Social Dimension: Building Connections and Fostering BondingRiddles are not just solitary pursuits; they are social activities that bring people together, fostering camaraderie and bonding through shared laughter and intellectual camaraderie. Whether exchanged around a campfire, during family gatherings, or as part of a team-building exercise,solving riddles encourages collaboration, communication, and collective problem-solving. In a world increasingly dominated by digital distractions, the simple pleasure of gathering with friends and loved ones to tackle a challenging riddle reminds us of the enduring power of human connection.Conclusion: Embracing the Enchantment of RiddlesIn conclusion, the allure of riddles transcends time and space, captivating hearts and minds with their tantalizing blend of mystery and mirth. From ancient rhapsodes to contemporary classrooms, the art of crafting and solving riddles continues to enrich our lives, fostering creativity, critical thinking, and social connection. As we navigate the complexities of the modern world, let us not forget to pause and revel in the joy of wordplay, for in the enigmatic embrace of a well-crafted riddle lies the promise of endless discovery and delight.Word Count: 815 words英文作文我爱猜字谜2:Great topic choice! Writing about English riddles can beboth fun and informative. Let's start by exploring the history and significance of riddles in English literature.Riddles have a long-standing tradition in English culture, dating back to ancient times. They were not only a form of entertainment but also served as a way to stimulate intellectual curiosity and challenge the mind. In Anglo-Saxon literature, riddles were often found in the form of enigmatic verses known as "exeter book riddles," named after the manuscript in which they were preserved. These riddles were often characterized by their clever wordplay and metaphorical language, inviting readers to decipher their hidden meanings.One of the most famous examples of Anglo-Saxon riddles is the riddle of the "River," which goes:"I am a wondrous creature for women in expectation, a service for neighbors. I harm none of the citizens except my slayer alone. My stem is erect, I stand up in bed, hairy somewhere down below. A very comely peasant's daughter, dares sometimes, proud maiden, that she grips at me, attacks me in my redness, plunders my head, confines me in astronghold, feels my encounter. Wet be that eye."Despite its seemingly obscure language, the answer to this riddle is "an onion," cleverly describing its appearance, function, and effect when chopped.Moving forward in time, riddles continued to be popular in medieval literature, often appearing in the works of Geoffrey Chaucer and William Shakespeare. Chaucer's "The Canterbury Tales" features several riddles, including the famous "The Riddle of the Nun's Priest," which humorously describes a rooster's crowing.In Shakespeare's works, riddles are used not only for entertainment but also as a means of characterization and plot development. In "Romeo and Juliet," for example, the playful exchange of riddles between Romeo and Juliet serves to highlight their intellectual connection and budding romance.In modern times, riddles remain a beloved form of entertainment, with countless books, websites, and apps dedicated to their enjoyment. From classic brain teasers tocontemporary puzzles, riddles continue to challenge and delight people of all ages.Beyond their entertainment value, riddles also serve educational purposes, helping to improve language skills, critical thinking, and problem-solving abilities. By deciphering the hidden meanings of riddles, readers are encouraged to think creatively and analytically, enhancing their cognitive abilities in the process.In conclusion, English riddles have a rich and storied history, spanning centuries of literary tradition. From their origins in Anglo-Saxon literature to their continued popularity in modern culture, riddles have captivated audiences with their clever wordplay and enigmatic charm. Whether as a source of amusement, intellectual stimulation, or educational enrichment, the enduring appeal of English riddles speaks to their timeless significance in the world of literature and beyond.。

坐海盗船的描写优美句子1.海盗船在波涛汹涌的大海上翱翔，船身随着波浪摇摆。

The pirate ship soars on the rough sea, its body swaying with the waves.2.船上的海盗们手握利剑，眼神中闪烁着野性和不羁。

The pirates on the ship wielded their swords, their eyes flashing with wildness and recklessness.3.海盗船的帆布在风中猎猎作响，指引着船只向着未知的冒险前进。

The sails of the pirate ship fluttered in the wind, guiding the ship towards unknown adventures.4.乌黑的旗帜迎风飘扬，象征着海盗的霸气与不羁。

The black flag flew in the wind, symbolizing the dominance and recklessness of the pirates.5.海盗船在夜色中穿行，星光点点，犹如一艘梦幻般的幽灵船。

The pirate ship sailed through the night, with stars twinkling, like a dreamlike ghost ship.6.海盗船的甲板上洒满了鲜血，船员们面带凶煞。

The deck of the pirate ship was splattered with blood, and the crew members had ferocious expressions.7.海盗船在阳光下闪耀着金色的光芒，宛如一艘光辉灿烂的风帆船。

The pirate ship shone with golden light in the sunlight, like a magnificent sailing ship.8.海盗船上的船长面容威严，他的眼神中透露着无尽的野心和欲望。

寻找失物英语作文模板英文回答：How to Find Lost Items。

Losing something important can be a stressful and frustrating experience. Whether it's a valuable possession, a sentimental keepsake, or even just a pair of keys, the loss can be a major inconvenience. Fortunately, there are a number of steps you can take to increase your chances of finding your lost item.1. Retrace Your Steps。

The first step is to retrace your steps and think back to the last place you remember having the item. This may involve revisiting the places you've been recently, such as your home, office, or the store where you think you might have left it.2. Check Common Hiding Places。

Once you've retraced your steps, it's time to check common hiding places. This includes under furniture, behind appliances, in drawers and cabinets, and inside pockets and bags. Sometimes, lost items can turn up in the most unexpected places.3. Ask Family and Friends。

可疑币鉴别流程Detecting and identifying suspicious coins is a process that requires careful attention to detail and a keen eye for potential fraud. Coin authentication is a crucial aspect of numismatics and the broader financial world, as counterfeit coins can severely impact the value and trustworthiness of currency systems. As such, it is important to establish a robust and comprehensive coin authentication process to safeguard against fraudulent activity. 鉴别和识别可疑的硬币是一个需要仔细注意细节和对潜在欺诈有犀利眼光的过程。

硬币鉴定是货币学和更广泛的金融世界中至关重要的一个方面，因为假冒硬币会严重影响货币系统的价值和信誉。

因此，建立一个健全和全面的硬币鉴别过程对抗欺诈活动至关重要。

The first step in the coin authentication process is to conduct a visual inspection of the coin. This involves examining the coin for any irregularities in its design, minting marks, and overall appearance. Additionally, it is important to compare the coin to known authentic examples to look for discrepancies. By conducting a thorough visual inspection, numismatists and coin collectors can identify potential counterfeit coins and take the necessary steps to further authenticatethem.硬币鉴别过程的第一步是对硬币进行视觉检查。