原题地址:https://oj.leetcode.com/problems/path-sum/ 题意: 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 =…

Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from C unlimited number of times. Note: All numbers (including target) will…

class Solution: # @param {integer[]} nums # @param {integer} target # @return {integer[]} def twoSum(self, nums, target): intLen=len(nums) if intLen <=1: return False res=[] dicts={} for i in range(0,intLen): if not dicts.has_key(target-nums[i]): dic…

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 / \ \…

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…

题目来源 https://leetcode.com/problems/path-sum-ii/ Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. 题意分析 Input: a binary tree, sum Output: list of list. Conditions: 给定一个二叉树,将所有root-leaf的路径值和等于sum的路径返…

题目来源 https://leetcode.com/problems/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. 题意分析 Input: a binary tree, sum Output: True or False Con…

题目来源 https://leetcode.com/problems/minimum-path-sum/ 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…

题目来源: https://leetcode.com/problems/binary-tree-maximum-path-sum/ 题意分析: 给定一棵树,找出一个数值最大的路径,起点可以是任意节点或者叶子. 题目思路: 我们可以先找路径的最大mr,ml,那么最大值是max(solve(root),solve(left),solve(right), max(mr + root.val + ml, root.val)). 代码(python): # Definition for a binary…

题目来源 https://leetcode.com/problems/combination-sum-ii/ 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 combina…