MATRIX67大神:   http://www.matrix67.com/blog/archives/5900

Chessboard

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

Problem Description

Consider the problem of tiling an n×n chessboard by polyomino pieces that are k×1 in size; Every one of the k pieces of each polyomino tile must align exactly with one of the chessboard squares. Your task is to figure out the maximum number of chessboard squares
tiled.

Input

There are multiple test cases in the input file.

First line contain the number of cases T (T≤10000).

In the next T lines contain T cases , Each case has two integers n and k. (1≤n,k≤100)

Output

Print the maximum number of chessboard squares tiled.

Sample Input

2
6 3
5 3

Sample Output

36
24

Source

BestCoder Round #17

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>

using namespace std;

int main()
{
	int T_T;
	int n,k;
	scanf("%d",&T_T);
	while(T_T--)
	{
		scanf("%d%d",&n,&k);
		if(k>n)
		{
			puts("0");
			continue;
		}
		int r=n%k;
		if(r>k/2) r=k-r;
		printf("%d\n",n*n-r*r);
	}
	return 0;
}