codevs 3143 二叉树的序遍历

#include <iostream>
#include <vector>
#include <sstream>
#include <string>
#include <cmath>
#include <stack>
using namespace std;

int pan[17]={0};
int l[17];
int r[17];
///先根访问节点，
///对节点是访问 对树是遍历子树
///最简单的访问shi输出
void qianxu(int i)
{
cout<<i<<" ";
if(l[i]) qianxu(l[i]);
if(r[i]) qianxu(r[i]);
    return ;
}
void zhongxu(int i)
{
if(l[i]) zhongxu(l[i]);
cout<<i<<" ";
if(r[i]) zhongxu(r[i]);
    return ;
}
void houxu(int i)
{
if(l[i]) houxu(l[i]);
if(r[i]) houxu(r[i]);
cout<<i<<" ";
    return ;
}

int main()
{
int n;
cin>>n;
for(int i=1;i<=n;++i)
{
    cin>>l[i]>>r[i];
}
qianxu(1);
cout<<endl;
zhongxu(1);
cout<<endl;
houxu(1);
cout<<endl;
return 0;
}