James Pan

原题网址：https://leetcode.com/problems/evaluate-reverse-polish-notation/Evaluate the value of an arithmetic expression in Reverse Polish Notation.Valid operators are +, -, *, /. Each operand m

原题网址：https://leetcode.com/problems/shortest-palindrome/Given a string S, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrom

原题网址：https://leetcode.com/problems/implement-strstr/Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.方法：KMP算法。p