HDU 1512 Monkey King

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#define maxn 100500
using namespace std;
int root[maxn],ls[maxn],rs[maxn],val[maxn],father[maxn],n,m;
int x,y,dis[maxn];
int find(int x)
{
if (x!=father[x])
father[x]=find(father[x]);
return father[x];
}
int merge(int x,int y)
{
if (x==0) return y;
else if (y==0) return x;
if (val[x]<val[y]) swap(x,y);
rs[x]=merge(rs[x],y);
father[rs[x]]=x;
if (dis[ls[x]]<dis[rs[x]]) swap(ls[x],rs[x]);
if (rs[x]==0) dis[x]=0;
else dis[x]=dis[rs[x]]+1;
return x;
}
int pop(int x)
{
father[x]=x;
father[ls[x]]=ls[x];
father[rs[x]]=rs[x];
int regis=merge(ls[x],rs[x]);
ls[x]=rs[x]=dis[x]=0;
return regis;
}
int main()
{
while (scanf("%d",&n)!=EOF)
{
memset(ls,0,sizeof(ls));
memset(rs,0,sizeof(rs));
dis[0]=-1;
for (int i=1;i<=n;i++)
{
scanf("%d",&val[i]);
father[i]=i;
root[i]=i;
}
scanf("%d",&m);
for (int i=1;i<=m;i++)
{
scanf("%d%d",&x,&y);
int pa,pb;
pa=find(x),pb=find(y);
if (pa==pb) printf("-1\n");
else
{
val[pa]/=2;val[pb]/=2;
int nn1,nn2;
nn1=pop(pa);nn2=pop(pb);
nn1=merge(nn1,pa);
nn1=merge(nn1,pb);
nn1=merge(nn1,nn2);
printf("%d\n",val[find(pa)]);
}
}
}
return 0;
}