题目:http://codeforces.com/problemset/problem/622/F 发现 sigma(i=1~n) i 是一个二次的多项式( (1+n)*n/2 ),sigma(i=1~n) i^2 是一个三次的多项式,所以 sigma(i=1~n) i^k 是一个k+1次的多项式.用拉格朗日插值就能做了. 注意别弄成 n^2 的.其实就是移动一个位置的时候乘一个数除以一个数,这样的. #include<iostream> #include<cstdio> #inc…

题目:http://codeforces.com/contest/622/problem/F 设 f(x) = 1^k + 2^k + ... + n^k 则 f(x) - f(x-1) = x^k 因为差值是 k 次的,所以 f 的次数应该是 k+1: 算出 k+2 个值就可以用拉格朗日插值求解了: 但是 k^2 会 T: #include<iostream> #include<cstdio> #include<cstring> #include<algorit…

The Sum of the k-th Powers There are well-known formulas: , , . Also mathematicians found similar formulas for higher degrees. Find the value of the sum modulo 109 + 7 (so you should find the remainder after dividing the answer by the value 109 + 7).…

Return the length of the shortest, non-empty, contiguous subarray of A with sum at least K. If there is no non-empty subarray with sum at least K, return -1. Example 1: Input: A = [1], K = 1 Output: 1 Example 2: Input: A = [1,2], K = 4 Output: -1 Exa…

Return the length of the shortest, non-empty, contiguous subarray of A with sum at least K. If there is no non-empty subarray with sum at least K, return -1. Example 1: Input: A = [1], K = 1 Output: 1 Example 2: Input: A = [1,2], K = 4 Output: -1 Exa…

https://leetcode.com/problems/shortest-subarray-with-sum-at-least-k/ 首先回顾一下求max子数组的值的方法是:记录一个前缀min值,然后扫一遍sum数组. 1.首先这里不需要最大,因为刚好够k就好了 2.这里需要距离最短.就是数组的长度最短. 这里的思路也一样,不过保存很多个min值,就是用一个队列,保存前缀的min值,不需要最min,只不过有更小的就更好. 也就是如果sum数组的值是: ..... 60, 40.....Y..…

Return the length of the shortest, non-empty, contiguous subarray of A with sum at least K. If there is no non-empty subarray with sum at least K, return -1. Example 1: Input: A = [1], K = 1 Output: 1 Example 2: Input: A = [1,2], K = 4 Output: -1 Exa…

Return the length of the shortest, non-empty, contiguous subarray of A with sum at least K. If there is no non-empty subarray with sum at least K, return -1. Example 1: Input: A = [1], K = 1 Output: 1 Example 2: Input: A = [1,2], K = 4 Output: -1 Exa…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 暴力求解 日期 题目地址:https://leetcode-cn.com/problems/two-sum-less-than-k/ 题目描述 Given an array A of integers and integer K, return the maximum S such that there exists i < j with A[i] +…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 队列 日期 题目地址:https://leetcode.com/problems/shortest-subarray-with-sum-at-least-k/ 题目描述 Return the length of the shortest, non-empty, contiguous subarray of A with sum at least K.…