LeetCode102-二叉树层次遍历详解

/*
* @lc app=leetcode.cn id=102 lang=cpp
*/

// 定义二叉树节点结构
struct TreeNode {
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
};

class Solution {
public:
// 主函数，返回二叉树的层次遍历结果
std::vector> levelOrder(TreeNode* root) {
std::vector> result;
if (root == nullptr) return {};
std::queue queue;
queue.push(root);

while (!queue.empty()) {
std::vector levelValues;
int levelSize = queue.size(); // 当前层的节点数量
for (int i = 0; i TreeNode* currentNode = queue.front();
queue.pop();
levelValues.push_back(currentNode->val);
if (currentNode->left != nullptr) queue.push(currentNode->left);
if (currentNode->right != nullptr) queue.push(currentNode->right);
}
result.push_back(levelValues);
}
return result;
}
};