与L2-006近乎相同，先建树，然后遍历

#include<bits/stdc++.h>
using namespace std;
int in[35];
int pre[35];
typedef struct Tree{int num;Tree* left;Tree* right;
}T;T * build(int in1,int in2,int pre1,int pre2){T * t=new T;t->num=pre[pre1];int key=pre[pre1];int i=0;for(i=in1;i<=in2;i++){if(in[i]==key){break;}}int num_node=i-in1;if(i!=in1){t->left=build(in1,i-1,pre1+1,pre1+num_node);}if(i!=in2){t->right=build(i+1,in2,pre1+num_node+1,pre2);}return t;
}
void visit(T * t){if(t == NULL){return ;}queue<T*> q;q.push(t);while(!q.empty()){T* tt=q.front();cout<<tt->num;if(tt->right  != NULL){q.push(tt->right);}if(tt->left  != NULL){q.push(tt->left);}q.pop();if(!q.empty()){cout<<' ';}}}
int main(){int n;cin>>n;for(int i=0;i<n;i++){cin>>in[i];}for(int i=0;i<n;i++){cin>>pre[i];}T * root=build(0,n-1,0,n-1);visit(root);return 0;
}