题解

/*
--------lzhledfz--------
*/
#include<bits/stdc++.h>
using namespace std;
struct am{
    int left,right;
};
am tree[1010];
void a(int root){
    if(root==0)return ;
    cout<<root<<" ";
    a(tree[root].left);
    a(tree[root].right);
}
void b(int root){
    if(root==0)return ;
    b(tree[root].left);
    cout<<root<<" ";
    b(tree[root].right);
}
void c(int root){
    if(root==0)return ;
    c(tree[root].left);
    c(tree[root].right);
    cout<<root<<" ";
}
int main(){
	int n,root=1;
    cin>>n;
    for(int i=0;i<n;i++){
        int l,r,v;
        cin>>v>>l>>r;
        tree[v].left=l;
        tree[v].right=r;
    }
    a(root);
    cout<<endl;
    b(root);
    cout<<endl;
    c(root);
    cout<<endl;
	return 0;
}