227. 基本计算器 II 实现一个基本的计算器来计算一个简单的字符串表达式的值. 字符串表达式仅包含非负整数,+, - ,*,/ 四种运算符和空格 . 整数除法仅保留整数部分. 示例 1: 输入: "3+2*2" 输出: 7 示例 2: 输入: " 3/2 " 输出: 1 示例 3: 输入: " 3+5 / 2 " 输出: 5 说明: 你可以假设所给定的表达式都是有效的. 请不要使用内置的库函数 eval. PS: 每次处理完一个数就压栈,可以…

227. 基本计算器 II 227. Basic Calculator II 题目描述 实现一个基本的计算器来计算一个简单的字符串表达式的值. 字符串表达式仅包含非负整数,+,-,*,/ 四种运算符和空格.整数除法仅保留整数部分. LeetCode227. Basic Calculator II中等 示例 1: 输入: "3+2*2" 输出: 7 示例 2: 输入: " 3/2 " 输出: 1 示例 3: 输入: " 3+5 / 2 " 输出:…

基本计算器II 实现一个基本的计算器来计算一个简单的字符串表达式的值. 字符串表达式仅包含非负整数,+, - ,*,/ 四种运算符和空格  . 整数除法仅保留整数部分. 示例 1: 输入: "3+2*2" 输出: 7 示例 2: 输入: " 3/2 " 输出: 1 示例 3: 输入: " 3+5 / 2 " 输出: 5 说明: 你可以假设所给定的表达式都是有效的. 请不要使用内置的库函数 eval. class Solution { public…

题目链接: https://leetcode-cn.com/problems/basic-calculator-ii 难度:中等 通过率:33.2% 题目描述: 实现一个基本的计算器来计算一个简单的字符串表达式的值. 字符串表达式仅包含非负整数,+, - ,*,/ 四种运算符和空格 ` `. 整数除法仅保留整数部分. 示例: 示例 1: 输入: "3+2*2" 输出: 7 示例 2: 输入: " 3/2 " 输出: 1 示例 3: 输入: " 3+5 /…

Implement a basic calculator to evaluate a simple expression string. The expression string contains only non-negative integers, +, -, *, / operators and empty spaces . The integer division should truncate toward zero. You may assume that the given ex…

Given a 2D board and a list of words from the dictionary, find all words in the board. Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same le…

There are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pair: [0,1] Given the total number of courses and a l…

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example, Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ]] 解题思路: 参考Java for LeetCode 054 Spiral Matrix,修改下…

Given two words (start and end), and a dictionary, find all shortest transformation sequence(s) from start to end, such that: Only one letter can be changed at a time    Each intermediate word must exist in the dictionary For example, Given:start = "…

Implement a basic calculator to evaluate a simple expression string. The expression string contains only non-negativeintegers, +, -, *, / operators and empty spaces . The integer division should truncate toward zero. Example 1: Input: "3+2*2" Ou…