Suppose that all the keys in a binary tree are distinct positive integers. Given the postorder and inorder traversal sequences, you are supposed to output the level order traversal sequence of the corresponding binary tree.
Input Specification:
Each input file contains one test case. For each case, the first line gives a positive integer N (≤30), the total number of nodes in the binary tree. The second line gives the postorder sequence and the third line gives the inorder sequence. All the numbers in a line are separated by a space.
Output Specification:
For each test case, print in one line the level order traversal sequence of the corresponding binary tree. All the numbers in a line must be separated by exactly one space, and there must be no extra space at the end of the line.
Sample Input:
7
2 3 1 5 7 6 4
1 2 3 4 5 6 7
Sample Output:
4 1 6 3 5 7 2
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <string>
#include <cctype>
#include <string.h>
#include <cstdio>
using namespace std;
struct node{
int index,value;
};
bool cmp(node a,node b){
return a.index<b.index;
}
vector<int> post,in;
vector<node> ans;
void pre(int root,int start,int end,int index){
if(start>end) return;
int i=start;
while(i<end&&in[i]!=post[root]) i++;
ans.push_back({index,post[root]});//顺序要一致
pre(root-(end-i+1),start,i-1,2*index+1);
pre(root-1,i+1,end,2*index+2);
}
int main(){
int n;
cin>>n;
post.resize(n);
in.resize(n);
for(int i=0;i<n;i++) cin>>post[i];
for(int i=0;i<n;i++) cin>>in[i];
pre(n-1,0,n-1,0);
sort(ans.begin(),ans.end(),cmp);
for(int i=0;i<ans.size();i++){
if(i) cout<<" ";
cout<<ans[i].value;
}
return 0;
}