合作网络（Corporative Network ）并查集+路径压缩

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

const int maxn = 20000 + 5;
int fa[maxn];
int d[maxn];

int Find(int x){
    if (fa[x] != x){
        int root = Find(fa[x]);
        d[x] += d[fa[x]];    //路径压缩维护d[i]
        return fa[x] = root;
    }
    else
        return x;
}

int main(){
    /*
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    */
    int t;
    cin >> t;
    while (t--){
        int n;
        cin >> n;
        
        //init
        for (int i = 1; i <= n; i++){
            fa[i] = i;
            d[i] = 0;
        }

        string s;
        while (cin >> s){
            if (s[0] == 'O')
                break;
            if (s[0] == 'I'){
                int a, b;
                cin >> a >> b;
                fa[a] = b;
                d[a] = abs(a - b) % 1000;
            }
            else{
                int c;
                cin >> c;
                Find(c);
                cout << d[c] << endl;
            }
        }
    }
    /*
    fclose(stdin);
    fclose(stdout);
    */
    return 0;
}