ＮＵＯＪ　1242 Interference Signal (信号强度) （第八届河南省程序设计）

Interference Signal

时间限制：2000 ms | 内存限制：65535 KB

难度：1

描述

Dr.Kong’s laboratory monitor some interference signals. The interference signals can be digitized into a series of positive integer. May be, there are N integers a1,a2,…,an.

Dr.Kong wants to know the average strength of a contiguous interference signal block. the block must contain at least M integers.

Please help Dr.Kong to calculate the maximum average strength, given the constraint.

输入

The input contains K test cases. Each test case specifies:

* Line 1: Two space-separated integers, N and M.

* Lines2~line N+1: ai (i=1,2,…,N)

1 ≤ K≤ 8, 5 ≤ N≤ 2000, 1 ≤ M ≤ N, 0 ≤ ai ≤9999

输出

For each test case generate a single line containing a single integer that is 1000 times the maximal average value. Do not perform rounding.

样例输入

2

10 6

6

4

2

10

3

8

5

9

4

1

5 2

10

3

8

5

9

样例输出

6500

7333

来源
第八届河南省程序设计大赛

题解：求至少m个连续的平均信号强度最大

代码：

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define LL long long
LL shu[4200],he[4200];
int n,k,m;
int main()
{
scanf("%d",&k);
while (k--)
{
scanf("%d%d",&n,&m);
he[0]=0;
for (int i=1; i<=n; i++)
{
scanf("%lld",&shu[i]);
he[i]=he[i-1]+shu[i];///前1，2，3，4，---N的和
}
LL ma=0;
for (int i=m; i<=n; i++)
{
for (int j=0; j<=n-m&&i+j<=n; j++)
ma=max(ma,(he[j+i]-he[j])*1000/i);///至少m个的平均值最大
}
printf("%lld\n",ma);
}
return 0;
}