[LeetCode]Minimum Depth of Binary Tree

题目描述:(链接)

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.

解题思路:

/**
 * 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 == nullptr) return 0;
        int left_min = minDepth(root->left);
        int right_min = minDepth(root->right);
        if (left_min == 0 && right_min == 0) {
            return 1;
        }
        
        if (left_min == 0) {
            left_min = INT_MAX;
        }
        
        if (right_min == 0) {
            right_min = INT_MAX;
        }
        
        return min(left_min, right_min) + 1;
    }
};