Average of Levels in Binary Tree

最新推荐文章于 2022-09-15 21:16:55 发布

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最新推荐文章于 2022-09-15 21:16:55 发布

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原文链接：http://www.cnblogs.com/xlqtlhx/p/7814236.html

本文介绍了一种使用C++实现的方法，用于计算二叉树每一层节点的平均值。通过广度优先搜索（BFS）遍历二叉树，并记录每一层的节点值总和及数量，最终计算出各层的平均值。

C++:

/**
 * 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:
    vector<double> averageOfLevels(TreeNode* root) {
        vector<double> res;
        queue<TreeNode*> q;
        q.push(root);
        double sum,avg;
        while(!q.empty())
        {
            int num=q.size();
            sum=0;
            for(int i=0;i<num;i++)
            {
                TreeNode* temp=q.front();
                sum+=temp->val;
                q.pop();
                if(temp->left!=NULL)
                    q.push(temp->left);
                if(temp->right!=NULL)
                    q.push(temp->right);
                
            }
            avg=sum/num;  
            res.push_back(avg);
        }
        return res;
    }
};

def averageOfLevels(self, root):
    info = []
    def dfs(node, depth = 0):
        if node:
            if len(info) <= depth:
                info.append([0, 0])
            info[depth][0] += node.val
            info[depth][1] += 1
            dfs(node.left, depth + 1)
            dfs(node.right, depth + 1)
    dfs(root)

    return [s/float(c) for s, c in info]

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def averageOfLevels(self, root):
        """
        :type root: TreeNode
        :rtype: List[float]
        """
        queue=[]
        res=[]
        queue.append(root)
        while(len(queue)!=0):
            num=len(queue)
            sum=0
            for i in range(num):
                temp=queue[0]
                sum+=temp.val
                del queue[0]
                if temp.left:
                    queue.append(temp.left)
                if temp.right:
                    queue.append(temp.right)
            avg=sum/float(num)
            res.append(avg)
        return res

转载于:https://www.cnblogs.com/xlqtlhx/p/7814236.html