【并查集】 ZOJ 3789 Gears

#include <iostream>
#include <sstream>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <climits>
#define maxn 600005
#define eps 1e-5
#define mod 1000000007
#define INF 1e9
#define lowbit(x) (x&(-x))
#define min(a, b) (a>b ? b : a)
#define max(a, b) (a>b ? a : b)
#define PI acos(-1)
typedef long long LL;
using namespace std;

int pos[maxn], f[maxn];
int id[maxn], cnt[maxn];
int n, m;
char s[10];
void init(void)
{
int i;
for(i=0;i<maxn;i++){
f[i]=i;
id[i]=i;
pos[i]=1;
cnt[i]=1;
}
}
int find(int x)
{
int fa;
if(x!=f[x]) fa=find(f[x]);
else fa=x;
pos[x]=(pos[f[x]]+pos[x])%2;
f[x]=fa;
return fa;
}
void debug(void)
{
int i;
for(i=1;i<=4;i++)
printf("%d\n", pos[i]);
}
void solve(void)
{
int top=n+1, a, b, aa, bb, tmp1, tmp2, tmp;
while(m--){
scanf("%s",s);
if(s[0]=='S'){
scanf("%d",&tmp);
printf("%d\n", cnt[find(id[tmp])]);
continue;
}
if(s[0]=='D'){
scanf("%d",&tmp);
cnt[find(id[tmp])]--;
id[tmp]=top++;
continue;
}
if(s[0]=='L'){
scanf("%d%d",&a,&b);
aa=find(id[a]);
bb=find(id[b]);
if(aa==bb) continue;
else{
cnt[aa]+=cnt[bb];
cnt[bb]=0;
f[bb]=aa;
if(pos[id[a]]==pos[id[b]]) pos[bb]^=1;
}
continue;
}
scanf("%d%d",&a,&b);
aa=find(id[a]);
bb=find(id[b]);
if(aa!=bb){
printf("Unknown\n");
continue;
}
tmp1=(pos[aa]-pos[id[a]]+2)%2;
tmp2=(pos[bb]-pos[id[b]]+2)%2;
if(tmp1==tmp2) printf("Same\n");
else printf("Different\n");
}
}
int main(void)
{
while(scanf("%d%d",&n,&m)!=EOF){
init();
solve();
}
return 0;
}