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:…

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…

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…

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…

题目 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…

[问题]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. 输入: "3+2*2" 输出: 示例 : 输入: " 3/2 " 输出: [思路] 总体思路来说,我们遍历字符串的每个字符,注意:加减乘除以及空格的ASCII码 < '0'.如果这个字符为数字字符,需要将两个非数字字符之间的不包含空格的字符串变换成数值!表达式:num = num * 10 - '0' +…

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…

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…

题目描述 Leetcode 224 Leetcode 224: 这里想让我们实现一个基础的计算器,来计算给定的字符串. 给定的字符串中包含 ( ) + - 和非负整数和空格. # Example 1: # # Input: "1 + 1" # Output: 2 # Example 2: # # Input: " 2-1 + 2 " # Output: 3 # Example 3: # # Input: "(1+(4+5+2)-3)+(6+8)"…

[LeetCode]227. Basic Calculator II 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/basic-calculator-ii/description/ 题目描述: Implement a basic calculator to evaluate a simple exp…

这种题都要设置一个符号位的变量 224. Basic Calculator 设置数值和符号两个变量,遇到左括号将数值和符号加进栈中 class Solution { public: int calculate(string s) { stack<int> st; ,flag = ; ;i < s.size();i++){ '){ ; '){ num = num* + flag * (s[i] - '); i++; } res += num; i--; } else if(s[i] ==…

[1]LeetCode 136 Single Number 题意:奇数个数,其中除了一个数只出现一次外,其他数都是成对出现,比如1,2,2,3,3...,求出该单个数. 解法:容易想到异或的性质,两个相同的数异或为0,那么把这串数从头到尾异或起来,最后的数就是要求的那个数. 代码如下: class Solution { public: int singleNumber(vector<int>& nums) { ; ;i<nums.size();i++) sum ^= nums[i…

leetcode - 40. Combination Sum II - Medium descrition Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each number in C may only be used once in the combinat…

LeetCode 137. Single Number II(只出现一次的数字 II)…

LeetCode:路径总和II[113] 题目描述 给定一个二叉树和一个目标和,找到所有从根节点到叶子节点路径总和等于给定目标和的路径. 说明: 叶子节点是指没有子节点的节点. 示例:给定如下二叉树,以及目标和 sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 返回: [ [5,4,11,2], [5,8,4,5] ] 题目分析 首先是一个深度搜索,来把所有根节点到叶子节点的路径找出来,然后各自判断是否等于目标值,等于目标值的路径加入结果集中.这…

LeetCode:组合总数II[40] 题目描述 给定一个数组 candidates 和一个目标数 target ,找出 candidates 中所有可以使数字和为 target 的组合. candidates 中的每个数字在每个组合中只能使用一次. 说明: 所有数字(包括目标数)都是正整数. 解集不能包含重复的组合. 示例 1: 输入: candidates = [10,1,2,7,6,1,5], target = 8, 所求解集为: [ [1, 7], [1, 2, 5], [2, 6],…

实现一个基本的计算器来计算一个简单的字符串表达式. 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. 你可以假定所给定的表达式总是有效的. 一些例子: "3+2*2" = 7" 3/2 " = 1" 3+5 / 2 " = 5注意: 不要使用eval 内置的函数库. 详见:https://leetcode.com/problems/basic-calculator-ii/description/ Jav…

Basic Calculator II 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 assu…

Problem Statement 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. Example 1: Inp…

［抄题］: 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. Example 1: Input: "3+2*2&q…

A 2d grid map of m rows and n columns is initially filled with water. We may perform an addLand operation which turns the water at position (row, col) into a land. Given a list of positions to operate, count the number of islands after each addLand o…

其他LeetCode题目欢迎访问:LeetCode结题报告索引 LeetCode:Word Ladder Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that: Only one letter can be changed at a time Each intermediate word…

LeetCode:Path Sum Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ \…

Work Break I Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words. For example, givens = "leetcode",dict = ["leet", "code"]. Return t…

原题链接在这里:Majority Element I,Majority Element II 对于Majority Element I 来说,有多重解法. Method 1:最容易想到的就是用HashMap 计数,数值大于n/2(注意不是大于等于而是大于),就是返回值.Time O(n), Space O(n). Method 2: 用了sort,返回sort后array的中值即可.Time O(n*logn), Space O(1). Method 3: 维护个最常出现值,遇到相同count+…

一. 题目 1. Two Sum II Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the ta…

I title: https://leetcode.com/problems/word-break/ Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words. For example, givens = "leetcode",dict = ["l…

Title: https://leetcode.com/problems/unique-paths/ A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bo…