diff --git a/problems/0222.完全二叉树的节点个数.md b/problems/0222.完全二叉树的节点个数.md index 998e22f3..ec68b6c6 100644 --- a/problems/0222.完全二叉树的节点个数.md +++ b/problems/0222.完全二叉树的节点个数.md @@ -335,6 +335,30 @@ func countNodes(root *TreeNode) int { } ``` +利用完全二叉树特性的递归解法 +```go +func countNodes(root *TreeNode) int { + if root == nil { + return 0 + } + leftH, rightH := 0, 0 + leftNode := root.Left + rightNode := root.Right + for leftNode != nil { + leftNode = leftNode.Left + leftH++ + } + for rightNode != nil { + rightNode = rightNode.Right + rightH++ + } + if leftH == rightH { + return (2 << leftH) - 1 + } + return countNodes(root.Left) + countNodes(root.Right) + 1 +} +``` + JavaScript: