#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct node
{
int id, l, r, index, level;
} a[100];
vector<node> v1;
void dfs(int root, int index, int level)
{
if (a[root].r != -1) dfs(a[root].r, index * 2 + 2, level + 1);
v1.push_back({root, 0, 0, index, level});
if (a[root].l != -1) dfs(a[root].l, index * 2 + 1, level + 1);
}
bool cmp(node a, node b)
{
if (a.level != b.level) return a.level < b.level;
return a.index > b.index;
}
int main()
{
int n, have[100] = {0}, root = 0;
cin >> n;
for (int i = 0; i < n; i++)
{
a[i].id = i;
string l, r;
cin >> l >> r;
if (l != "-")
{
a[i].l = stoi(l);
have[stoi(l)] = 1;
}
else
a[i].l = -1;
if (r != "-")
{
a[i].r = stoi(r);
have[stoi(r)] = 1;
}
else
a[i].r = -1;
}
while (have[root] == 1) root++;
dfs(root, 0, 0);
vector<node> v2(v1);
sort(v2.begin(), v2.end(), cmp);
for (int i = 0; i < v2.size(); i++)
{
if (i != 0) cout << " ";
cout << v2[i].id;
}
cout << endl;
for (int i = 0; i < v1.size(); i++)
{
if (i != 0) cout << " ";
cout << v1[i].id;
}
return 0;
}
学习代码
- 方法和一般的遍历一样, 只是先遍历右子树再遍历左子树
#include<iostream>
#include<vector>
#include<queue>
using namespace std;
vector<vector<int> > v(10);
vector<int> in, exist(10, 1), level;
void inOrder(int root)
{
if(root==-1) return;
if(v[root][1]!=-1) inOrder(v[root][1]);
in.push_back(root);
if(v[root][0]!=-1) inOrder(v[root][0]);
}
int main()
{
int n, i, root, left, right;
char l, r;
scanf("%d", &n);
for(i=0; i<n; i++)
{
cin>>l>>r;
left = l=='-' ? -1 : l-'0';
right = r=='-' ? -1 : r-'0';
if(left>=0)
exist[left]=0;
if(right>=0)
exist[right]=0;
v[i].push_back(left);
v[i].push_back(right);
}
for(i=0; i<n; i++) if(exist[i]) root=i;
queue<int> q;
q.push(root);
while(q.size())
{
int tmp=q.front();
q.pop();
level.push_back(tmp);
if(v[tmp][1]!=-1) q.push(v[tmp][1]);
if(v[tmp][0]!=-1) q.push(v[tmp][0]);
}
inOrder(root);
printf("%d", level[0]);
for(i=1; i<n; i++) printf(" %d", level[i]);
printf("\n%d", in[0]);
for(i=1; i<n; i++) printf(" %d", in[i]);
return 0;
}