1.描述

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.

2.分析

3.代码

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
int minDepth(struct TreeNode* root) {
    if (NULL == root) return 0;
    if (NULL == root->left) return minDepth(root->right) + 1;
    if (NULL == root->right) return minDepth(root->left) + 1;
    int left = minDepth(root->left);
    int right = minDepth(root->right);
    return left < right ? left +1 : right + 1;
}