[LeetCode] 111. Minimum Depth of Binary Tree

题目链接：传送门

Description

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

Solution

题意：

求二叉树的最小深度

思路：

dfs

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int minDepth(TreeNode* root) {
        if (!root)  return 0;
        if (!root->left)  return minDepth(root->right) + 1;
        if (!root->right)  return minDepth(root->left) + 1;
        int lDepth = minDepth(root->left);
        int rDepth = minDepth(root->right);
        return min(lDepth, rDepth) + 1;
    }
};