From any string, we can form a subsequence of that string by deleting some number of characters (possibly no deletions). Given two strings source and target, return the minimum number of subsequences of source such that their concatenation equals tar…

From any string, we can form a subsequence of that string by deleting some number of characters (possibly no deletions). Given two strings source and target, return the minimum number of subsequences of source such that their concatenation equals tar…

LeetCode: Reverse Words in a String:Evaluate Reverse Polish Notation Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, /. Each operand may be an integer or another expression. Some examples: ["2&q…

题目: 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 palindrome you can find by performing this transformation. For example: Given "aacecaaa", r…

Given two non-negative integers 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.…

[LeetCode]678. Valid Parenthesis String 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/valid-parenthesis-string/description/ 题目描述: Given a string containing only three types…

This is a follow up of Shortest Word Distance. The only difference is now word1 could be the same as word2. Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list. word1 and word2 may be…

This is a follow up of Shortest Word Distance. The only difference is now you are given the list of words and your method will be called repeatedly many times with different parameters. How would you optimize it? Design a class which receives a list…

Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list. For example,Assume that words = ["practice", "makes", "perfect", "coding", "makes"]. G…

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 palindrome you can find by performing this transformation. For example: Given "aacecaaa", return "aaacecaaa&qu…