Average of Levels in Binary Tree
给一个二叉树, 返回每层的均值. 直接层遍历即可.
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class Solution { public List<Double> averageOfLevels(TreeNode root) { Queue<TreeNode> q = new LinkedList<TreeNode>(); q.add(root); List<Double> res = new ArrayList<>(); while(!q.isEmpty()) { int size = q.size(); double sum = 0; for(int i = 0; i < size; i++) { TreeNode node = q.remove(); sum += node.val; if(node.left != null) q.add(node.left); if(node.right != null) q.add(node.right); } res.add(sum / size); } return res; } } |