[jobdu]二叉树的镜像

#include <iostream>
#include <vector>
using namespace std;

void preOrder(vector<vector<int> > &tree, vector<int> &val, vector<int> &ans, int root) {
if (root == -1) return;
else {
ans.push_back(val[root]);
preOrder(tree, val, ans, tree[root][1]);
preOrder(tree, val, ans, tree[root][0]);
}
}

int main() {
int n;
while (cin >> n)
{
vector<vector<int> > tree(n+1);
vector<int> val(n+1);
for (int i = 1; i <= n; i++) {
int tmp;
cin >> tmp;
val[i] = tmp;
}
for (int i = 1; i <= n; i++) {
char type;
cin >> type;
if (type == 'd') {
int x, y;
cin >> x >> y;
tree[i].push_back(x);
tree[i].push_back(y);
}
else if (type == 'l') {
int x;
cin >> x;
tree[i].push_back(x);
tree[i].push_back(-1);
}
else if (type == 'r') {
int x;
cin >> x;
tree[i].push_back(-1);
tree[i].push_back(x);
}
else if (type == 'z') {
tree[i].push_back(-1);
tree[i].push_back(-1);
}
}
if (n == 0) {
cout << "NULL" << endl;
continue;
}
vector<int> ans;
preOrder(tree, val, ans, 1);
for (int i = 0; i < ans.size() - 1; i++) {
cout << ans[i] << " ";
}
cout << ans[ans.size()-1] << endl;
}
}