每次出树的题目我都白给，好不容易遇到一道我会写的简单题QAQ

#include<iostream>
#include<stack>
using namespace std;
const int N=100;
int qian[N],zhong[N];
int cnt1,cnt2;
int hou[N];
int cnt;
stack<int> zz;
void build(int qianl,int qianr,int zhongl,int zhongr){
    if(zhongl>zhongr) return ;
    int u=qian[qianl];//父节点
    int k;
    for(k=zhongl;k<=zhongr;k++) {
        if(zhong[k]==u) break;
    }//找到了父节点在中序遍历里的位置
    build(qianl+1,qianl+1+(k-1-zhongl),zhongl,k-1);
    build(qianl+1+(k-1-zhongl)+1,qianr,k+1,zhongr);
    hou[cnt++]=u;
}
int main(){
    int n;
    cin>>n;
    for(int i=0;i<2*n;i++){
        string kk;
        cin>>kk;
        if(kk=="Push"){
            int x;
            cin>>x;
            qian[cnt1++]=x;
            zz.push(x);
        }
        else{
            int x=zz.top();
            zz.pop();
            zhong[cnt2++]=x;
        }
    }
    build(0,n-1,0,n-1);
    // for(int i=0;i<n;i++) cout<<qian[i]<<' ';
    // cout<<endl;
    // for(int i=0;i<n;i++) cout<<zhong[i]<<' ';
    cout<<hou[0];
    for(int i=1;i<cnt;i++) cout<<' '<<hou[i];
}
//知道前序中序求后序