104/111. Maximum / Minimum Depth of Binary Tree

104. Maximum Depth of Binary Tree

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Question

Total Accepted: 113363  Total Submissions: 242208  Difficulty: Easy

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

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  Tree Depth-first Search

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  (E) Balanced Binary Tree (E) Minimum Depth of Binary Tree

分析：

深度优先搜索，在写成递归时可以用前序式遍历

当前根节点的最大高度就是左子树有右子树中较大者

/**
 * 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(root==NULL)
            return 0;//深度优先搜索：前序方式遍历 
        if(root->right == NULL)  
            return maxDepth(root->left)+1;  
        if(root->left == NULL)
            return maxDepth(root->right)+1; 
        
        return 1+max(maxDepth(root->left),maxDepth(root->right));
    }
};

111. Minimum Depth of Binary Tree

My Submissions

Question

Total Accepted: 87963  Total Submissions: 293947  Difficulty: Easy

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.

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Hide Tags

  Tree Depth-first Search Breadth-first Search

Hide Similar Problems

  (E) Binary Tree Level Order Traversal (E) Maximum Depth of Binary Tree

分析：

依然深度优先搜索，在写成递归时可以用前序式遍历

当前根节点的最小高度就是左子树有右子树中较小者

/**
 * 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==NULL)  
            return 0;  
        if(root->left == NULL)
		    return minDepth(root->right)+1;
	    if(root->right == NULL)
		    return minDepth(root->left)+1;
        return 1+min(minDepth(root->left),minDepth(root->right));  //获取当前节点root的左右子树高度的较小者
    }
};

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原文地址：http://blog.csdn.net/ebowtang/article/details/50332803

原作者博客：http://blog.csdn.net/ebowtang