阳离子

摘要： 题目 给定一个字符串，请你找出其中不含有重复字符的最长子串的长度 思路 unordered__set 具备set互异性的特点，同时对插入的数据保留原顺序，即unordered。 本题的思想为“滑动窗口”，用unordered_set记录已扫描的字符，在插入前判断当前字符是否存在在已扫描的序列中。若存 阅读全文

摘要： 题目 给定两个单词 word1 和 word2，计算出将 word1 转换成 word2 所使用的最少操作数 。 你可以对一个单词进行如下三种操作： 插入一个字符 删除一个字符 替换一个字符 思路 定义一个数组 代表第一个字符串前i个字符转换为第二个字符串前j个字符串所需要的缩少操作数。 如果wor 阅读全文

摘要： 题目 给定一个无重复元素的数组 candidates 和一个目标数 target ，找出 candidates 中所有可以使数字和为 target 的组合。 candidates 中的数字可以无限制重复被选取。 说明： 所有数字（包括 target）都是正整数。 解集不能包含重复的组合。 样例 示例 阅读全文

摘要： Suppose a bank has K windows open for service. There is a yellow line in front of the windows which devides the waiting area into two parts. All the c 阅读全文

摘要： Suppose a bank has N windows open for service. There is a yellow line in front of the windows which devides the waiting area into two parts. The rules 阅读全文

摘要： A reversible prime in any number system is a prime whose "reverse" in that number system is also a prime. For example in the decimal system 73 is a re 阅读全文

摘要： To evaluate the performance of our first year CS majored students, we consider their grades of three courses only: C Programming Language, Mathematics 阅读全文

摘要： It is vitally important to have all the cities connected by highways in a war. If a city is occupied by the enemy, all the highways from/toward that c 阅读全文

摘要： Given a pair of positive integers, for example, 6 and 110, can this equation 6 = 110 be true? The answer is , if 6 is a decimal number and 110 is a bi 阅读全文

摘要： Given a sequence of K integers { N 1, N 2, ..., N K }. A continuous subsequence is defined to be { N i , N i +1, ..., N j } where 1≤ i ≤ j ≤ K . The M 阅读全文