P2956 [USACO09OCT]The Robot Plow G 机器人耕地

#include<stdio.h>
#include<ctype.h>
#include<string.h>
#include<math.h>
#include<stdlib.h>

int main()
{
    int x, y, num, x1, y1, x2, y2, cnt = 0;
    scanf("%d %d %d", &x, &y, &num);
    int sign[x][y], i, j;
    for ( i = 0; i < x; i++)
        for ( j = 0; j < y; j++)
            sign[i][j] = 0;
    while(num){
        scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
        for ( i = x1 - 1; i <= x2 - 1; i++)
            for ( j = y1 - 1; j <= y2 - 1; j++)
                sign[i][j] = 1;
        num--;
    }
    for (i = 0; i < x; i++)
        for ( j = 0; j < y; j++){
            if ( sign[i][j] == 1)
                cnt++;
        }
    printf("%d", cnt);
    return 0;
}

也就是标记数组做标记，只不过成了二维数组。