贪心 FZU 2013 A short problem

 

题目传送门

 1 /*  2  题意：取长度不小于m的序列使得和最大  3  贪心：先来一个前缀和，只要长度不小于m，从m开始，更新起点k最小值和ans最大值  4 */  5 #include <cstdio>  6 #include <algorithm>  7 using namespace std;  8  9 const int MAXN = 1e6 + 10; 10 const int INF = 0x3f3f3f3f; 11 int a[MAXN], sum[MAXN]; 12 13 int main(void) //FZU 2013 A short problem 14 { 15 // freopen ("C.in", "r", stdin); 16 17 int t; scanf ("%d", &t); 18 while (t--) 19  { 20 int n, m; scanf ("%d%d", &n, &m); 21 for (int i=1; i<=n; ++i) 22  { 23 scanf ("%d", &a[i]); sum[i] = sum[i-1] + a[i]; 24  } 25 26 int k = 0; int ans = -INF; 27 for (int i=m; i<=n; ++i) 28  { 29 ans = max (ans, sum[i] - k); 30 k = min (k, sum[i-m]); 31  } 32 33 printf ("%d\n", ans); 34  } 35 36 return 0; 37 }