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.

 

给你一个二叉树，找到它的最浅深度

 

这个题目我采取的是用深度遍历的方法，把每次得到的深度保存起来即depth，如果depth小于len，我们就令len为depth，遍历整个二叉树

后得到的len就是最浅深度

 

/**
 * 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:
    void depthFirstSearch(TreeNode* root, int depth)
	{
		if (root == NULL)return;
		if (root->left)
		{
			depthFirstSearch(root->left, ++depth);
			depthFirstSearch(root->right, depth);
		}
		else
		{
			if (root->right)
			{
				depthFirstSearch(root->right, ++depth);
			}
			else
			{
				if (++depth < len)len = depth;
			}
		}
	}
	int minDepth(TreeNode* root) {
		int depth = 0;
		depthFirstSearch(root, depth);
		if(len==INT32_MAX)
		return 0;
		else
		return len;
	}
private:
	int len = INT32_MAX;
};