xtu 1264 Partial Sum 2017湘潭邀请赛E

Partial Sum Bobo has a integer sequence a1,a2,…,an of length n. Each time, he selects two ends 0≤l<r≤n and add |∑rj=l+1aj|−C into a counter which is zero initially. He repeats the selection for at most m times. If each end can be selected at most once (either as left or right), find out the maximum sum Bobo may have. Input The input contains zero or more test cases and is terminated by end-of-file. For each test case: The first line contains three integers n, m, C. The second line contains n integers a1,a2,…,an. 2≤n≤105 1≤2m≤n+1 |ai|,C≤104 The sum of n does not exceed 106. Output For each test cases, output an integer which denotes the maximum. Sample Input 4 1 1 -1 2 2 -1 4 2 1 -1 2 2 -1 4 2 2 -1 2 2 -1 4 2 10 -1 2 2 -1 Sample Output 3 4 2 0

#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
 
#define ll __int64
const int N=100005;
 
int main()
{
    ll n,m,c,a,sum[N];
    while(~scanf("%I64d %I64d %I64d",&n,&m,&c))
    {
        sum[0]=0;
        for(int i=1; i<=n; i++)
        {
            scanf("%I64d",&a);
            sum[i]=sum[i-1]+a;
        }
        sort(sum,sum+n+1);
        int l=n,s=0;
        ll ans=0;
        for(int i=0; i