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Solution103.cpp
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38 lines (36 loc) · 978 Bytes
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//
// Solution103.cpp
// Algorithm
//
// Created by Pancf on 2020/11/15.
// Copyright © 2020 Pancf. All rights reserved.
//
#include "Solution103.hpp"
#include <queue>
std::vector<std::vector<int>> Solution103::zigzagLevelOrder(TreeNode *root)
{
std::vector<std::vector<int>> res;
if (!root) return res;
std::queue<TreeNode *> q;
TreeNode *sentinel = (TreeNode *)0;
q.push(root);
q.push(sentinel);
int layer = 0;
std::vector<int> values;
while (!q.empty()) {
TreeNode *node = q.front();
q.pop();
if (node == sentinel) {
if (!q.empty()) q.push(sentinel);
if (layer & 1) std::reverse(values.begin(), values.end());
res.push_back(values);
values.clear();
layer++;
} else {
values.push_back(node->val);
if (node->left) q.push(node->left);
if (node->right) q.push(node->right);
}
}
return res;
}