Files
OI-source/2.548.cpp
2023-08-03 09:22:52 +08:00

57 lines
969 B
C++

#include<iostream>
#include<string>
#include<sstream>
#include<algorithm>
using namespace std;
const int maxv=10000+10;
int in_order[maxv],post_order[maxv],lch[maxv],rch[maxv];
int n;
bool read_list(int *a)
{
string line;
if(!getline(cin,line)) return 0;
stringstream ss(line);
n=0;
int x;
while(ss>>x) a[n++]=x;
return n>0;
}
int build(int L1,int R1,int L2,int R2)
{
if(L1>R1) return 0;
int root=post_order[R2];
int p=L1;
while(in_order[p]!=root) p++;
int cnt=p-L1;
lch[root]=build(L1,p-1,L2,L2+cnt-1);
rch[root]=build(p+1,R1,L2+cnt,R2-1);
return root;
}
int best,best_sum;
void dfs(int u,int sum)
{
sum+=u;
if(!lch[u]&&!rch[u])
{
if(sum<best_sum||(sum==best_sum&&u<best))
{
best=u;
best_sum=sum;
}
}
if(lch[u]) dfs(lch[u],sum);
if(rch[u]) dfs(rch[u],sum);
}
int main()
{
while(read_list(in_order))
{
read_list(post_order);
build(0,n-1,0,n-1);
best_sum=1000000000;
dfs(post_order[n-1],0);
cout<<best<<endl;
}
return 0;
}