2014 Super Training #8 A Gears --并查集

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
using namespace std;
#define N 600007
#define M 33

int fa[N],n,m,dis[N];
int num[N],mp[N];

int findset(int x)
{
    if(x != fa[x])
    {
        int tmp = findset(fa[x]);
        dis[x] += dis[fa[x]];  //累加距离
        fa[x] = tmp;
    }
    return fa[x];
}

void init()
{
    for(int i=0;i<=n+m;i++)
    {
        fa[i] = i;
        num[i] = 1;
        dis[i] = 0;
        mp[i] = i;
    }
}

int main()
{
    int i,u,v,k;
    char ss[5];
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        init();
        int now = n+1;
        while(m--)
        {
            scanf("%s",ss);
            if(ss[0] == ‘L‘)
            {
                scanf("%d%d",&u,&v);
                u = mp[u];  //实际的位置
                v = mp[v];
                int fx = findset(u);
                int fy = findset(v);
                if(fx != fy)
                {
                    fa[fx] = fy;
                    //dis[fx] = dis[fy]+1; //1
                    //dis[u] = dis[v]+1;   //2  **1,2顺序不能反，或者直接用下面**
                    dis[fx] = dis[u]+dis[v]+1;   //与根距离之和的奇偶性再反一下，得出相对距离的奇偶性
                    num[fy] += num[fx];
                }
            }
            else if(ss[0] == ‘Q‘)
            {
                scanf("%d%d",&u,&v);
                u = mp[u];    //实际的位置
                v = mp[v];
                int fx = findset(u);
                int fy = findset(v);
                if(fx != fy)
                    puts("Unknown");
                else
                {
                    if(abs(dis[u]-dis[v]) & 1)
                        puts("Different");
                    else
                        puts("Same");
                }
            }
            else if(ss[0] == ‘S‘)
            {
                scanf("%d",&u);
                int tu = mp[u];
                printf("%d\n",num[findset(tu)]);
            }
            else
            {
                scanf("%d",&v);
                int tv = mp[v];
                num[findset(tv)]--;
                mp[v] = now++;
            }
        }
    }
    return 0;
}