hdu 1512 左偏树

#include<iostream>
#include<cstdio>
#define maxn 100001
using namespace std;
int f[maxn];
int find(int x)
{
int r=x;
while(f[r]!=r)r=f[r];
while(x!=r)
{
f[x]=r;
x=f[x];
}
return r;
}
int val[maxn],dis[maxn];
int l[maxn],r[maxn];
int merge(int x,int y)
{
if(x*y==0) return x+y;
if(val[x]<val[y]) swap(x,y);
r[x]=merge(r[x],y);
f[r[x]]=x;
if(dis[r[x]]>dis[l[x]]) swap(r[x],l[x]);
if(r[x])dis[x]=dis[r[x]]+1;
else dis[x]=0;
return x;
}
int del(int x)
{
int L=l[x],R=r[x];
f[L]=L;f[R]=R;
dis[x]=l[x]=r[x]=0;
return merge(L,R);
}
void solve(int x,int y)
{
int rx=del(x);
val[x]/=2;
x=merge(rx,x);
int ry=del(y);
val[y]/=2;
y=merge(ry,y);
printf("%d\n",val[merge(x,y)]);
}
int main()
{
int n;
while(scanf("%d",&n)!=EOF)
{
for(int i=1;i<=n;i++)
{
f[i]=i;
dis[i]=l[i]=r[i]=0;
scanf("%d",&val[i]);
}
int m;
scanf("%d",&m);
int u,v,fu,fv;
for(int i=1;i<=m;i++)
{
scanf("%d%d",&u,&v);
int fu=find(u),fv=find(v);
if(fu!=fv)
solve(fu,fv);
else puts("-1");
}
}
return 0;
}