Path Sum OJ: https://oj.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. For example: Given the below binary tree and…

今天在浏览网页的时候,发现了一个叫做  华为面试题(8分钟写出代码) 的链接,不确定真实性,纯属好奇,就点进去看看 这个可能是很老的题目吧,因为我看到这题目时,底下有好多评论了.提到XX排序,内存占用,等等词汇 小丑是新人,也想用自己的方法解一下题目,如有雷同,纯属巧合 解: (1) 有前辈在解题时用到排序,但我认为没有必要,排序后的sum(a) - sum(b), 与任意杂乱顺序的sam(a) - sam(b) 结果肯定是一致的 ; (2) 如果 c[i] = a[i] - b[i]  , …

有两个数组a,b,大小都为n,数组元素的值任意整形数,无序: 要求:通过交换a,b中的元素,使数组a元素的和与数组b元素的和之间的差最小. 当前数组a和数组b的和之差为    A = sum(a) - sum(b) a的第i个元素和b的第j个元素交换后,a和b的和之差为    A' = sum(a) - a[i] + b[j] - (sum(b) - b[j] + a[i])           = sum(a) - sum(b) - 2 (a[i] - b[j])           = A…

Path Sum Total Accepted: 81706 Total Submissions: 269391 Difficulty: Easy 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…

Given an integer N, the task is to find out the count of numbers M that satisfy the condition M + sum(M) + sum (sum(M)) = N, where sum(M) denotes the sum of digits in M. Input:The first line of input contains an integer T denoting the number of test…

Path Sum 题目链接 题目要求: 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 /…

今天的模拟赛里T2要使用到数论分块,里面有一个重要的坎就是关于r=sum/(sum/l)的证明,网上关于这道题的题解里都没有关于这个的证明,那么我就来填补一下: 在以下的文章里,我都会使用lo(x)表示对x向下取整,同理up(x)表示对x向上取整; 我们要求左右区间的边界,那么我们就不妨设 取两个数 i 和 i‘ 使得lo(N/i')==lo(N/i)则,我们就可以证明 设 lo(N/i)=k;则有  k*i+p=N   (p一定有  0<=p<i 成立)   设i’=i+d  则有   lo…

文章目录 Two Sum Two Sum II 3Sum 4Sum Two Sum 题意 给定一个数组,和指定一个目标和.从数组中选择两个数满足和为目标和.保证有且只有一个解.每个元素只可以用一次. 思路 Hash表快速查询值是否在数组中存在. 枚举一个数,查询另一个数是否存在. 注意:虽然一个元素只可以使用一次,但是数组中可以出现重复的元素. 复杂度 T(N)=O(N),M(N)=O(N)T(N)=O(N),M(N)=O(N)T(N)=O(N),M(N)=O(N) 结果 Runtime: 5…

Problem 1 [Balanced Binary Tree] Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Pr…

39. Combination 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 (inc…