题解 | #二叉树的最大深度#

• 迭代法
• 层序遍历，记录层数，最终结果为最大深度。

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 */

class Solution {
public:
    /**
     * 
     * @param root TreeNode类 
     * @return int整型
     */
    int maxDepth(TreeNode* root) {
        // write code here
        if (root == NULL) return 0;
        int result = 0;
        queue<TreeNode*> que;
        que.push(root);
        while (!que.empty()) {
            int size = que.size();
            result++;
            for (int i = 0; i < size; i++) {
                TreeNode* node = que.front();
                que.pop();
                if (node->left) que.push(node->left);
                if (node->right) que.push(node->right);
            }
        }
        return result;
    }
};