CodeForces 566D 并查集集合合并

 #include <stdio.h>
 #include <algorithm>
 #define MAX 100000
 #define LL long long
 #define unsigned U
 //using namespace std;
 int cas=,T;
 int fa[MAX*+],next[MAX*+],n,q;
 void init(int n)
 {
     for(int i=;i<=n;i++) { fa[i]=i;next[i]=i+; }
 }
 int find(int x)
 {
     return fa[x]==x?x:(fa[x]=find(fa[x]));
 }
 void merge(int x,int y)
 {
     if(x>y) std::swap(x,y);
     for(int i=x+;i<=y;)
     {
         int xx=find(i);
         int yy=find(i-);
         fa[xx]=fa[yy]=std::min(xx,yy);
         int tmp=next[i];
         next[i]=next[y];
         i=tmp;
     }
 }
 int main()
 {
     //freopen("1.in","w",stdout);
     //freopen("1.in","r",stdin);
     //freopen("1.out","w",stdout);
     //scanf("%d",&T);
     while(scanf("%d%d",&n,&q)==)
     {
         init(n);
         int t,x,y;
         while(q--)
         {
             scanf("%d%d%d",&t,&x,&y);
             if(t==) puts(find(x)==find(y)?"YES":"NO");
             else if(t==) merge(x,y);
             else
             {
                 int xx=find(x);
                 int yy=find(y);
                 fa[xx]=fa[yy]=std::min(xx,yy);
             }
         }
     }
     //printf("time=%.3lf",(double)clock()/CLOCKS_PER_SEC);
     return ;
 }