【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.

求一棵树的最小深度，即从根结点到叶节点路径中，最短路径中结点的个数。思路是先求得左右子树的最小深度，然后取两者更小值加1作为整棵树的最小深度，但要注意左子树或右子树为空时的处理。

/** * 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) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        if (!root)return 0;int leftdep = minDepth(root->left);int rightdep = minDepth(root->right);if (leftdep==0 && rightdep==0)return 1;if (leftdep == 0) leftdep = INT_MAX;if (rightdep == 0) rightdep = INT_MAX;return min(leftdep,rightdep)+1;    }};