637. Average of Levels in Binary Tree

解題說明

C++ 解法

複雜度分析

虛擬碼

1. Initialize result as empty array
2. If root is null: return result
3. Initialize queue q and push root
4. While q is not empty:
   a. sz = q.size()  (number of nodes at current level)
   b. sum = 0.0 (use double)
   c. For i from 0 to sz-1:
      i.  node = q.front(); q.pop()
      ii. sum += node.val
      iii. If node.left exists: push node.left
      iv.  If node.right exists: push node.right
   d. Append (sum / sz) to result
5. Return result

其他解法

延伸思考