FZU2013 short problem

Problem Description

The description of this problem is very short. Now give you a string(length N), and ask you the max sum of the substring which the length can‘t small than M.

 Input

The first line is one integer T(T≤20) indicates the number of the test cases. Then for every case, the first line is two integer N(1≤N≤1000000) and M(1≤M≤N).

Then one line contains N integer indicate the number. All the number is between -10000 and 10000.

 Output

Output one line with an integer.

 Sample Input

2 5 1 1 -2 -2 -2 1 5 2 1 -2 -2 -2 1

 Sample Output

1 -1

 Source

FOJ有奖月赛-2011年03月

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<map>
#include<string>
#include<cmath>
using namespace std;
int a[1000010];

int main()
{
    int n,m;
    int T;
    scanf("%d", &T);
    while(T--){
        scanf("%d%d", &n, &m);
        for(int i = 1; i <= n ; i++)
            scanf("%d", &a[i]);
        for(int i = 1; i <= n ;i++){
            a[i] += a[i-1];
        }
        int t = 0;
        int ans = -1;
        for(int i = m; i <= n ; i++){
            ans = max(ans , a[i] - t);
            t = min(t, a[i-m]);
        }
        printf("%d\n", ans);
    }
    return 0;
}