leetCode(17):Minimum/Maximize depth of binary tree 分类： leetCode 2015-06-21 16:05 146人阅读 评论(0) 收藏

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.

/**
 * 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) {
        queue<TreeNode*> nodes;
    	if(NULL==root)
    		return 0;
    	nodes.push(root);
    	int i=1;//记录深度
    	while(!nodes.empty())
    	{
    		int length=nodes.size();
    		int j=0;
    		
    		while(j<length)
    		{
    			TreeNode* tmpNode=nodes.front();
    			if(!tmpNode->left && !tmpNode->right)
    				return i;//左右子树均为空，直接返回其深度
    			if(tmpNode->left)
    				nodes.push(tmpNode->left);
    			if(tmpNode->right)
    				nodes.push(tmpNode->right);
    					
    			nodes.pop();
    			j++;
    		}
    		
    		i++;
    	}
    	return i;
    }
};

/**
 * 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 maxDepth(TreeNode* root) {
        if(NULL==root)
    		return 0;
    	int left=maxDepth(root->left);//先求左右子树的深度
    	int right=maxDepth(root->right);
    	
    	return 1+(left>right?left:right);
    }
};

最大最小深度的求法不一样。