这一套题做错了几次,按理说直接用等差数列求和公式就行了,主要是要考虑一些运算符的结核性问题: 四则运算符(+.-.*./)和求余运算符(%)结合性都是从左到右. 于是,我自己写了一个版本,主要是考虑(n+1)*n始终为偶数,这样就不用担心除以2时的取整问题: #include <stdio.h> int main(void) { int n; __int64 sum = ; while (scanf("%d", &n) != EOF) { sum = ((n + )…

Sum Problem Time Limit: 1000/500 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 338086    Accepted Submission(s): 85117 Problem Description Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge). In this pro…

这一段时间一直都在刷OJ,这里建一个博客合集,用以记录和分享算法学习的进程. github传送门:https://github.com/haoyuanliu/Online_Judge/tree/master/HangDianOJ   Problem Description In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n. Input The input will consist of a series…

#include <stdio.h> int main(){ int k,sum; while(scanf("%d",&k)!=EOF){ ==){ sum=(+k)*(k/); } else{ sum=(+k)*(k/)+k/+; } printf("%d\n\n",sum); } ; }…

/* 注意可以是负整数,而且在过程中会超过int,所以要用longlong */ #include <cstdio> int main() { long long n; while (scanf("%lld",&n)!=EOF) (n<1)?printf("%d\n\n",(n+1)*(2-n)/2):printf("%d\n\n",n*(n+1)/2); return 0; }…

I found summary of k Sum problem and solutions in leetcode on the Internet. http://www.sigmainfy.com/blog/summary-of-ksum-problems.html…

https://en.wikipedia.org/wiki/Subset_sum_problem In computer science, the subset sum problem is an important problem in complexity theory and cryptography. The problem is this: given a set (or multiset) of integers, is there a non-empty subset whose…

The sum problem Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 12422 Accepted Submission(s): 3757 Problem Description Given a sequence 1,2,3,......N, your job is to calculate all the possible sub…

We have a lot of ways to solve the maximum subsequence sum problem, but different ways take different time. 1.Brute-force algorithm int maxSubSum1(const vector<int> &a) { int maxSum=0; for(int i=0;i<a.size();i++) for(int j=i;j<a.size();j++…

The sum problem Problem Description Given a sequence 1,2,3,......N, your job is to calculate all the possible sub-sequences that the sum of the sub-sequence is M.   Input Input contains multiple test cases. each case contains two integers N, M( 1 <=…