[LeetCode] Minimum Depth of Binary Tree

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.

解法:参照http://blog.csdn.net/sbitswc/article/details/26526031

/**
 * Definition for binary tree
 * 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 == NULL) return 0;
        
        int left_depth = minDepth(root->left);
        int right_depth = minDepth(root->right);
    
        if (left_depth == 0 && right_depth == 0)
            return 1;
        if (left_depth == 0)
            left_depth = INT_MAX;
        if (right_depth == 0)
            right_depth = INT_MAX;
            
        return min(left_depth, right_depth) + 1;
    }
};