题意 你和你的朋友玩一个游戏,游戏规则如下. 你的朋友创造 n 个长度均为 m 的不相同的字符串,然后他随机地选择其中一个.他选择这些字符串的概率是相等的,也就是说,他选择 n 个字符串中的每一个的概率是 1/n .你想猜猜你的朋友选择了哪个字符串. 为了猜到你的朋友选择了哪个字符串,你可以问他问题,形式如下:字符串中第 pos 个字符是什么?当问题的答案为唯一标识字符串时,我们认为这个字符串是猜测的.在字符串被猜测后,你将停止提问. 你没有一个特殊的策略,所以你每次可能会等概率的问任何一个你从…

题目大意:甲和乙玩游戏,甲给出n(n<=50)个等长的字符串(len<=20),然后甲选出其中一个字符串,乙随机询问该字符串某一位的字符(不会重复询问一个位置),求乙能确定该串是哪个字符串的询问次数的期望值 这题不看题解好难想......(感谢zhx和zhx两位大佬的题解) len很小,考虑状压DP,显然我们要状压询问,要定义两个状态,f[]和num[] 1表示询问,0表示未询问 那么,我们定义f[s]表示询问状态s距离确定一个字符串所需要的期望值. 定义tot是s状态剩余的询问的次数,那么显…

March 18, 2016 Problem statement: https://www.hackerrank.com/challenges/two-strings/submissions/code/18506948 Julia likes to try a new way to train herself to expand C#/ C++ / Java / JavaScript languages, by reading the solutions, followed up with so…

StackOverFlow排错翻译 - Python字符串替换: How do I replace everything between two strings without replacing the strings? 原创连接: Python字符串替换 问题: Python:如何将两字符串之间的内容替换掉? I have this string(问题源码): str = ''' // DO NOT REPLACE ME // Anything might be here. Numbers…

Given two numbers represented as strings, return multiplication of the numbers as a string. Note: The numbers can be arbitrarily large and are non-negative. Converting the input string to integer is NOT allowed. You should NOT use internal library su…

Given two non-negative numbers num1 and num2 represented as string, return the sum of num1 and num2. Note: The length of both num1 and num2 is < 5100. Both num1 and num2 contains only digits 0-9. Both num1 and num2 does not contain any leading zero.…

Design an algorithm to encode a list of strings to a string. The encoded string is then sent over the network and is decoded back to the original list of strings. Machine 1 (sender) has the function: string encode(vector<string> strs) { // ... your…

Given a string, we can "shift" each of its letter to its successive letter, for example: "abc" -> "bcd". We can keep "shifting" which forms the sequence: "abc" -> "bcd" -> ... -> &quo…

Given two strings s and t, determine if they are isomorphic. Two strings are isomorphic if the characters in s can be replaced to get t. All occurrences of a character must be replaced with another character while preserving the order of characters.…

Given two numbers represented as strings, return multiplication of the numbers as a string. Note: The numbers can be arbitrarily large and are non-negative. 这道题让我们求两个字符串数字的相乘,输入的两个数和返回的数都是以字符串格式储存的,这样做的原因可能是这样可以计算超大数相乘,可以不受int或long的数值范围的约束,那么我们该如何来计算…