UVALive 3027 Corporative Network（并查集之四）

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<string.h>
#define MOD 1000
#define MAX 20000
int pre[MAX+7],dist[MAX+7];
int find(int x)
{
    int r=x;
    while(r!=pre[r])
        r=pre[r];
    if(x==r)
        dist[x]=0;
    else
        dist[x]=dist[x]+find(pre[x]);
    int i=x,j;
    while(i!=r)
    {
        j=pre[i];
        pre[i]=r;
        i=j;
    }
    return dist[x];
}
void mix(int x,int y)
{
    pre[x]=y;
}
int main()
{
    int n,T;
    char c;
    while(scanf("%d",&T)!=EOF)
    {
        while(T--)
        {
            scanf("%d",&n);
            getchar();
            for(int i=1;i<=n;i++)
                pre[i]=i;
            while(1)
            {
                c=getchar();
                if(c==‘I‘)
                {
                    int x,y;
                    scanf("%d%d",&x,&y);
                    getchar();
                    dist[x]=abs(x-y)%MOD;
                    mix(x,y);
                }
                else if(c==‘E‘)
                {
                    int x;
                    scanf("%d",&x);
                    getchar();
                    printf("%d\n",find(x));
                }
                else break;
            }
        }
    }
    return 0;
}