C语言铺地毯问题竞赛题改编

救命，这题没思路，不知道咋写，求救

#include <stdio.h>

#define N 50

int main()
{
    int n, m;
    int a[N][N] = {};
    scanf("%d%d", &n, &m);
    for (int i = 0; i < m; i++)
    {
        int x1, y1, x2, y2;
        scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
        for (int j = y1; j <= y2; j++)
            for (int k = x1; k <= x2; k++)
                a[j][k]++;
    }
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
            printf("%d ", a[i][j]);
        printf("\n");
    }
    return 0;
}