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Copy pathtree_order.cpp
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71 lines (66 loc) · 1.72 KB
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//
// Created by 宋峰 on 2018/9/25.
//
#include <vector>
#include <iostream>
#include "../tree/tree.cpp"
using namespace std;
void pre_order(TreeNode *root) {
vector<TreeNode *> stack;
TreeNode *p = root;
while (p != nullptr) {
while (p != nullptr) {
stack.push_back(p);
cout << p->val << " ";
p = p->left;
}
while (p == nullptr) {
TreeNode *top = stack[stack.size() - 1];
stack.pop_back();
p = top->right;
if (stack.size() == 0)
break;
}
}
}
void middle_order(TreeNode *root) {
vector<TreeNode *> stack;
TreeNode *p = root;
while (p != nullptr) {
while (p != nullptr) {
stack.push_back(p);
p = p->left;
}
while (p == nullptr) {
TreeNode *top = stack[stack.size() - 1];
stack.pop_back();
cout << top->val << " ";
p = top->right;
if (stack.size() == 0) {
break;
}
}
}
}
void post_order(TreeNode *root) {
vector<TreeNode *> stack;
TreeNode *cur = root;
TreeNode *pre = nullptr;
stack.push_back(cur);
while (stack.size() > 0) {
cur = stack[stack.size() - 1];
if ((cur->left == nullptr && cur->right == nullptr) ||
(pre != nullptr && (pre == cur->left || pre == cur->right))) {
cout << cur->val << " ";
stack.pop_back();
pre = cur;
} else {
if (cur->right != nullptr) {
stack.push_back(cur->right);
}
if (cur->left != nullptr) {
stack.push_back(cur->left);
}
}
}
}