柯森锎的博客

题目描述Implement regular expression matching with support for ‘.’ and ‘*’.‘.’ Matches any single character. ‘*’ Matches zero or more of the preceding element.The matching should cover the entire input st

题目描述Implement wildcard pattern matching with support for ‘?’ and ‘*’.‘?’ Matches any single character. ‘*’ Matches any sequence of characters (including the empty sequence).The matching should cover t

参考《算法导论》动态规划章节。 判断一个问题能否用动态规划解决，要求问题满足两个条件： 1）存在最优子结构，即一个问题可以通过n（n>=1）个选择划分成n或n+1个同类子问题+选择代价； 2）存在重叠子问题，不同的问题会重复调用同一个子问题；动态规划解决问题的步骤： 1）刻画一个最优解的结构特征，即寻找一个最优子结构； 2）一个递归求解方案； 3）计算最优解的值，两种方法

题目描述Given a string containing just the characters ‘(’ and ‘)’, find the length of the longest valid (well-formed) parentheses substring.For “(()”, the longest valid parentheses substring is “()”, which