思维题 Gym 100553A Alter Board

 

题目传送门

/*
    题意：一个n×m的矩形，相邻的颜色不同，黑或白。问最少的翻转次数，每次翻转可指定任意一个子矩形
    思维题：最少要把偶数行和列翻转，也就是n/2+m/2次
*/
#include <cstdio>
using namespace std;

int main(void)        //Gym 100553A Alter Board
{
//    freopen ("A.in", "r", stdin);
    freopen ("alter.in", "r", stdin);
    freopen ("alter.out", "w", stdout);

    int n, m;
    while (scanf ("%d%d", &n, &m) == 2)
    {
        printf ("%d\n", n / 2 + m / 2);
        for (int i=2; i<=n; i+=2)
        {
            printf ("%d %d %d %d\n", i, 1, i, m);
        }
        for (int i=2; i<=m; i+=2)
        {
            printf ("%d %d %d %d\n", 1, i, n, i);
        }
    }

    return 0;
}