666666666666666666

解题思路:

注意事项:

参考代码:

#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

const int N=1e6+10;

int n, m;

int p[N];

int findth(int x)

{

if (x == p[x]) return x;

return p[x] = findth(p[x]);

}

int unionn(int x, int y)

{

int xx = findth(x);

int yy = findth(y);

if (xx != yy) {

p[yy] = xx;

return 1;

}

return 0;

}

int main()

{

scanf("%d %d", &n, &m);

for (int i = 1;i <= n * m;i++) p[i] = i;

int x1, y1, x2, y2;

while (scanf("%d %d %d %d", &x1, &y1, &x2, &y2) == 4) {

unionn((x1 - 1)*m + y1, (x2 - 1)*m + y2);

}

int sum = 0;

for (int i = 1;i <= m;i++) {

for (int j = 1;j < n;j++) {

if (unionn((j - 1)*m + i, j*m + i))

sum++;

}

}

for (int i = 1;i <= n;i++) {

for (int j = 1;j < m;j++) {

if (unionn((i - 1)*m + j, (i - 1)*m + j + 1) ) sum += 2;

}

}

printf("%d\n", sum);

return 0;

}