E. Rectangle
Time Limit: 1000ms
Memory Limit: 65536KB
64-bit integer IO format:
%lld Java class name:
Main
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 \(n, m, k\) (\(1 \leq n, m \leq 5 \cdot 10^4, 0 \leq k \leq 10^9\)).
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 156256250062500000
有技巧的暴力题，暴力一条边的长度，那么另外一条边的情况就能算出来了。
#include<iostream>
using namespace std;
int main()
{
long long n,m,k;
while(cin >> n >> m >> k)
{
k/=2;
long long ans = 0;
for(int i=1;i<=n&&k-i>0;i++)
{
long long j = min(k-i,m);
long long a = n-i+1;
long long b = (m+(m-j+1))*j/2;
ans+=a*b;
}
cout<<ans<<endl;
}
return 0;
}