思路: 递归解决,如果左括号个数小于右括号或者左括号数小于总括号对数,则生成一个左括号,如果左括号数大于右括号,生成一个右括号. class Solution { public: vector<string> ans; int num; void brackets(string res, int left, int right, int sum) { * num) { ans.push_back(res); } else{ , right, sum + ); , sum + ); } } ve…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 22: Generate Parentheseshttps://oj.leetcode.com/problems/generate-parentheses/ Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For exa…

22. Generate Parentheses . Generate Parentheses Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = , a solution set is: [ "((()))", "(()())", "(())()"…

一.题目说明 这个题目是22. Generate Parentheses,简单来说,输入一个数字n,输出n对匹配的小括号. 简单考虑了一下,n=0,输出"";n=1,输出"()":n=2,输出"()()","(())"... 二.我的解法 我考虑了一下,基本上2种思路,其1是暴力破解法,就是列出所有可能情况,然后判断哪些是匹配的. 汗颜的是,我没做出来.找到的答案: #include<iostream> #incl…

一.题目说明 题目79. Word Search,给定一个由字符组成的矩阵,从矩阵中查找一个字符串是否存在.可以连续横.纵找.不能重复使用,难度是Medium. 二.我的解答 惭愧,我写了很久总是有问题,就先看正确的写法,下面是回溯法的代码: class Solution { public: int m,n; //左 上 右 下 int dx[4] = {-1,0,1,0}; int dy[4] = {0,1,0,-1}; bool exist(vector<vector<char>&g…

Generate Parentheses Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: "((()))", "(()())", "(())()", "()(())", "…

Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be us…

Word Search Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell m…

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: [ "((()))", "(()())", "(())()", "()(())", "()()()" ] AC…

Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be us…