LA 3027 并查集

比较基础的带权并查集，需要注意终止条件是'O'而不是'0'...

#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;

const int N = 20001;
const int MOD = 1000;
int f[N];
int d[N];

void init( int n )
{
    for ( int i = 1; i <= n; i++ )
    {
        f[i] = i;
        d[i] = 0;
    }
}

void findf( int x )
{
    if ( f[x] == x ) return ;
    int tx = f[x];
    findf(tx);    
    d[x] += d[tx];
    f[x] = f[tx];
}

int main ()
{
    int t;
    scanf("%d", &t);
    while ( t-- )
    {
        int n;
        scanf("%d", &n);
        init(n);
        char op[2];
        while ( scanf("%s", op) != EOF )
        {
            if ( op[0] == 'O' ) break;
            int x, y;
            if ( op[0] == 'E' )
            {
                scanf("%d", &x);
                findf(x);
                printf("%d
", d[x]);
            }
            else
            {
                scanf("%d%d", &x, &y);
                f[x] = y;
                d[x] = ( ( int ) abs( x - y ) ) % MOD;
            }
        }
    }
    return 0;
}