题目:Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + nums[1] = 2 + 7 = 9, return [0, 1] 代码:(1.22) /** * @param {number[]} nums * @param {number} target * @return {number[]} */ var twoSum = function(nums, target) {//给定两个参数nums,target var resu…

剑指offer 65. 不用加减乘除做加法(Leetcode 371. Sum of Two Integers) https://leetcode.com/problems/sum-of-two-integers/ 题目: 写一个函数,求两个整数之和,要求在函数体内不得使用加减乘除这四个符号. 分析: 对于不能使用正常的四则运算符,一般就是使用位运算了.而本题要想实现加法,只能使用异或了. 需要注意的是,加法的时候涉及进位,而进位的实现利用与运算. 此外,进位之后还有可能产生进位,所以要在循环里…

1.Two sum (Easy)# Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. Example: Given num…

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 / \ \…

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. Note: You can only move either down or right at any point in time. 思路:由于只能向两个方向走,瞬间就没有了路线迂回的烦恼,题目的难度…

Given an array of integers, 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 target, where index1 must be less than index2. Please note that…

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 / \ \ 7 2 1 return true…

题目: Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -. Example:Given a = 1 and b = 2, return 3. 代码: 使用移位来计算,用异或求不带进位的和,用与并左移1位来算进位,然后将两者相加. class Solution { public: int getSum(int a, int b) { ? a : getSum(…

原题链接 题意: 给定一个值,求出从树顶到某个叶(没有子节点)有没有一条路径等于该值. 思路: DFS Runtime: 4 ms, faster than 100.00% of C++ class Solution { public: bool hasPathSum(TreeNode *root, int sum) { if (root == NULL) return false; if (root->val == sum && root->left==NULL &&…

Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2). Range Sum Query 2D The above rectangle (with the red border) is defined by (row1, col1) = (…