BNUOJ---E. Rectangle

E. Rectangle

Time Limit: 1000ms

Memory Limit: 65536KB

64-bit integer IO format: %lld      Java class name: Main

题意：给定矩形的最大周长，求长n宽m中所含满足要求的矩形的个数：
思路：矩形的性质：（对边相等）枚举k/2的半周长，代码如下；

frog has a piece of paper divided into n rows and m columns. Today, she would like to draw a rectangle whose perimeter is not greater than k .

 

 

There are 8 (out of 9 ) ways when n=m=2,k=6

 

Find the number of ways of drawing.

Input

The input consists of multiple tests. For each test:

 

The first line contains 3 integer n,m,k ( 1≤n,m≤5⋅104,0≤k≤109 ).

Output

For each test, write 1 integer which denotes the number of ways of drawing.

Sample Input

2 2 6
1 1 0
50000 50000 1000000000

Sample Output

8
0
1562562500625000000

Submit Status

#include <iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#define LL long long
using namespace std;

int main()
{
   LL n,m,k;
   LL ans;
   LL y;
   while(~scanf("%lld%lld%lld",&n,&m,&k))
   {
       ans=0;
       LL l=k/2;
       LL tmp;
       for(LL i=1;i<=n&&i<=l;i++)
       {
            y=min(l-i,m);
            tmp=(m+1-y+m)*(y)/2;
           ans+=tmp*(n+1-i);
       }
       printf("%lld\n",ans);
   }
    return 0;
}