Minimum Depth of Binary Tree

最新推荐文章于 2025-08-07 13:22:03 发布

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最新推荐文章于 2025-08-07 13:22:03 发布

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文章标签： c/c++ java

原文链接：http://www.cnblogs.com/zlz-ling/p/4043240.html

本文详细介绍了使用C++和Java两种语言实现计算二叉树最小深度的方法，通过递归和广度优先搜索算法找到从根节点到最近叶子节点的最短路径长度。

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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.

C++版：

#include <iostream>

using namespace std;
struct TreeNode {
   int val;
   TreeNode *left;
   TreeNode *right;
   TreeNode(int x):val(x),left(NULL),right(NULL) {}
};

class Solution {
public:
     int minDepth(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(root)
        {
            if(root->left == NULL && root->right == NULL)
                return 1;
            else if(root->left == NULL)
                return minDepth(root->right) + 1;
            else if(root->right == NULL)
                return minDepth(root->left) + 1;
            return min(minDepth(root->left), minDepth(root->right)) + 1;
        }
        return 0;

    }
};

int main(){
    TreeNode *a = new TreeNode(1);
    TreeNode *b = new TreeNode(2);
    TreeNode *c = new TreeNode(3);
    TreeNode *d = new TreeNode(4);
    TreeNode *e = new TreeNode(5);
    TreeNode *f = new TreeNode(6);
    TreeNode *g = new TreeNode(7);

    a->left = b;
    a->right = c;
    b->left = d;
    b->right = e;
    c->left = f;
    c->right = g;
    Solution s1;
    int s = s1.minDepth(a);
    cout<<"the minDepth of the tree is:"<<s<<endl;
    return 0;
}

　　Java版：

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public int minDepth(TreeNode root) {
        if( root == null) {
            return 0;
        }
        
        LinkedList<TreeNode> nodes = new LinkedList<TreeNode>();
        LinkedList<Integer> counts = new LinkedList<Integer>();
        
        nodes.add(root);
        counts.add(1);
        
        while(!nodes.isEmpty()) {
            TreeNode curr = nodes.remove();
            int count = counts.remove();
            
            if(curr.left != null) {
                nodes.add(curr.left);
                counts.add(count + 1);
            }
            
            if(curr.right != null) {
                nodes.add(curr.right);
                counts.add(count + 1);
            }
            
            if(curr.left == null && curr.right == null) {
                return count;
            }
        }
        return 0;
    }
}

转载于:https://www.cnblogs.com/zlz-ling/p/4043240.html