【LeetCode】111 - 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.

Solution:

1.递归

 /**
  * 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 ;
         else if(root->left && !root->right)
             return +minDepth(root->left);
         else if(!root->left && root->right)
             return +minDepth(root->right);
         else
             return +min(minDepth(root->right),minDepth(root->left));
     }
 };

2.栈，待续