LeetCode Minimum Depth of Binary Tree

最新推荐文章于 2023-12-15 03:22:29 发布

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本文介绍如何通过递归的方式找到给定二叉树的最小深度，即从根节点到最近叶子节点的最短路径长度。代码示例中包含了两种实现方式，详细解释了每个步骤和关键逻辑。

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 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) {
        if(root == NULL)
            return 0;
        else if(root->left == NULL && root->right == NULL)
            return 1;
        else if(root->left != NULL && root->right == NULL)
            return minDepth(root->left)+1;
        else if(root->left == NULL && root->right != NULL)
            return minDepth(root->right)+1;
        else
            return min(minDepth(root->left), minDepth(root->right))+1;
        
    }
private:
    int min(const int& a, const int& b) {
        return a < b? a : b;
    }
        
};

第二次写这个类：

/**
 * 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) {
        if(root == NULL)
            return 0;
        else if(root->left == NULL)
            return minDepth(root->right)+1;
        else if(root->right == NULL)
            return minDepth(root->left)+1;
        else
            return min(minDepth(root->left), minDepth(root->right))+1;
        
    }
private:
    int min(const int& a, const int& b) {
        return a < b? a : b;
    }
        
};