hdoj 5630 Rikka with Chess 【水题】

Rikka with Chess

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)

Total Submission(s): 280    Accepted Submission(s): 240

Problem Description

Yuta gives Rikka a chess board of size n×m.

As we all know, on a chess board, every cell is either black or white and every two cells that share a side have different colors.

Rikka can choose any rectangle formed by board squares and perform an inversion, every white cell becomes black, and vice versa.

Rikka wants to turn all cells into the same color, please tell Rikka the minimal number of inversions she need to achieve her goal.

 

Input

The first line contains a number T(T≤10) ——The number of the testcases.

Each testcase contains two numbers n,m(n≤109,m≤109).

 

Output

For each testcase, print a single number which represents the answer.

 

Sample Input

31 22 23 3

 

Sample Output

122

 

题意：给定一个黑白相间的n*n尺寸的格子，每次操作可以任选一个矩形改变里面的颜色。问最少需要多少次操作使得所有格子变成同一种颜色。

AC代码：

#include <iostream>#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>using namespace std;int main(){    int t; cin >> t;    while(t--)    {        int n, m; cin >> n >> m;        cout << n / 2 + m / 2 << endl;    }    return 0;}