题目大意:给定一个 N 个值组成的序列,求序列中区间和相同的不相交区间段数量的最大值. 题解:设 \(dp[i][j]\) 表示到区间 [i,j] 时,与区间 [i,j] 的区间和相同的不相交区间数量是多少.可以枚举之前的区间进行状态转移,时间复杂度为 \(O(n^4)\). 代码如下 #include <bits/stdc++.h> using namespace std; const int maxn=51; int n,ans,x,y,a[maxn],sum[maxn],dp[maxn]…

题解:发现可以通过枚举区间将区间和相同的元组记录在一个表中,对于答案来说,在同一个表中的元组的选择才会对答案产生贡献.发现每一个表中都是一个个区间,问题转化成了对于每一个表来说,选择若干个不相交的区间,使得选择出来的区间数量最多,直接贪心即可. 代码如下 #include <bits/stdc++.h> using namespace std; typedef pair<int,int> P; const int maxn=1501; int n,a[maxn],sum[maxn]…

[LeetCode]129. Sum Root to Leaf Numbers 解题报告(Python) 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/sum-root-to-leaf-numbers/description/ 题目描述: Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a numbe…

404. Sum of Left Leaves [题目]中文版  英文版 /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: int sumOfLeftLea…

[题意]对于n个数,找出一些数使得它们的和能被n整除,输出任意一组方案,n<=10^6. [算法]构造/结论 [题解]引用自:http://www.cnblogs.com/Sakits/p/7407103.html by Sakits 对n个数求前缀和,即sum[i]=sigma(a[1~i])%n,若sum[i]=0则找到答案,否则n个前缀和填充1~n-1,根据抽屉原理必有两个前缀和相同,则中间那一段数字之和是n的倍数. #include<cstdio> ],a[]; int main…

[Description] 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 target,…

Difficulty: Easy  More:[目录]LeetCode Java实现 Description https://leetcode.com/problems/sum-of-square-numbers/submissions/ Given a non-negative integer c, your task is to decide whether there're two integers aand b such that a2 + b2 = c. Example 1: Inpu…

题目如下: 解题思路:我的想法对于数组中任意一个元素,找出其左右两边最近的小于自己的元素.例如[1,3,2,4,5,1],元素2左边比自己小的元素是1,那么大于自己的区间就是[3],右边的区间就是[4,5].那么对于元素2来说,和左边区间合并组成[2,3]以及和右边区间合并组成[2,4,5],这两段区间包括2在内的所有subarray的最小值都是2,其分别可以组成的subarry的个数是 len([3])和len([4,5]),左右区间合并在一起可以组成的subarray的个数是len([3])…

If the depth of a tree is smaller than 5, then this tree can be represented by a list of three-digits integers. For each integer in this list: The hundreds digit represents the depth D of this node, 1 <= D <= 4. The tens digit represents the positio…

题目简述: 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 retu…