HDU 5630 Rikka with Chess(翻棋子)

Rikka with Chess

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 639 Accepted Submission(s): 541

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

Source

BestCoder Round #73 (div.2) 

/*思路：刚看到题目被吓到，然后画图猜，发现这个规律，所以不要被题目吓到.. */#include<iostream>using namespace std;int main(){      int n,m,t;    cin>>t;    while(t--){    cin>>n>>m;    cout<<n/2+m/2<<endl;;}return 0;}