CF 并查集（或者图） Ice Skating

/*
Pro: 0

Sol:

date:
*/
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <queue>
#include <set>
#include <vector>
using namespace std;
int n,a,b,x[1111],y[1111],p[1111];
int find(int x) {return x == p[x] ? x : p[x] = find(p[x]);}
int main(){
scanf("%d",&n);
for(int i = 1; i <= n; i ++)
scanf("%d%d",&x[i],&y[i]),p[i] = i;
int ans=0;
for(int i = 1; i <= n; i ++){
for(int j = 1; j <= n; j ++){
if(x[i] == x[j] || y[i] == y[j]){
int px = find(i);
int py = find(j);
if(px!=py)
p[px] = py,ans++;
}
}
}
printf("%d\n",n-1-ans);
return 0;
}

#include <cstdio>
int n,x[1111],y[1111],vis[1111],ans;
void go(int indx){
vis[indx] = true;
//    printf("%d\n",indx);
for(int i = 1; i<= n; i ++)
if( (x[i] == x[indx] || y[i] == y[indx] )&& !vis[i])
go(i);
}
int main(){
scanf("%d",&n);
for(int i = 1; i <= n; i ++){
scanf("%d%d",x + i, y + i);
}
ans = -1;
for(int i = 1; i <= n; i ++){
if(!vis[i]) go(i),ans ++;
}
printf("%d\n",ans);
return 0;
}