注意，层序遍历那个也要是翻转后的

#include<bits/stdc++.h>
using namespace std;
struct node{
    int left,right;
}a[100];
bool f[100];
int n;
vector<int>level,in;
int convert(string s)
{
    int ans=0;
    if(isdigit(s[0]))
    {
        for(int i=0;i<s.length();i++)ans=ans*10+s[i]-'0';
    }
    else ans=-1;
    return ans;
}
void BFS(int root)
{
    queue<int>q;
    q.push(root);
    while(!q.empty())
    {
        int front=q.front();
        level.push_back(front);
        q.pop();
        if(a[front].right!=-1)q.push(a[front].right);
        if(a[front].left!=-1)q.push(a[front].left);
    }
}
void show(vector<int>a)
{
    for(int i=0;i<a.size();i++)
    {
        printf("%d",a[i]);
        if(i!=a.size()-1)printf(" ");
    }
    printf("\n");
}
void inorder(int root)
{
    if(root==-1)return;
    inorder(a[root].right);
    in.push_back(root);
    inorder(a[root].left);
}
int main()
{
    scanf("%d",&n);
    for(int i=0;i<n;i++)
    {
        string s1,s2;
        cin>>s1>>s2;
        a[i].left=convert(s1);
        if(a[i].left>=0)f[a[i].left]=true;
        a[i].right=convert(s2);
        if(a[i].right>=0)f[a[i].right]=true;
    }
    int root;
    for(int i=0;i<n;i++)
    {
        if(f[i]==false)
        {
            root=i;
            break;
        }
    }
    BFS(root);
    show(level);
    inorder(root);
    show(in);
    return 0;
}