diff --git a/problems/0110.平衡二叉树.md b/problems/0110.平衡二叉树.md index dd05bdd6..f8071333 100644 --- a/problems/0110.平衡二叉树.md +++ b/problems/0110.平衡二叉树.md @@ -623,6 +623,8 @@ class Solution: ``` ### Go: +递归法 + ```Go func isBalanced(root *TreeNode) bool { h := getHeight(root) @@ -653,6 +655,64 @@ func max(a, b int) int { } ``` +迭代法 + +```Go +func isBalanced(root *TreeNode) bool { + st := make([]*TreeNode, 0) + if root == nil { + return true + } + st = append(st, root) + for len(st) > 0 { + node := st[len(st)-1] + st = st[:len(st)-1] + if math.Abs(float64(getDepth(node.Left)) - float64(getDepth(node.Right))) > 1 { + return false + } + if node.Right != nil { + st = append(st, node.Right) + } + if node.Left != nil { + st = append(st, node.Left) + } + } + return true +} + +func getDepth(cur *TreeNode) int { + st := make([]*TreeNode, 0) + if cur != nil { + st = append(st, cur) + } + depth := 0 + result := 0 + for len(st) > 0 { + node := st[len(st)-1] + if node != nil { + st = st[:len(st)-1] + st = append(st, node, nil) + depth++ + if node.Right != nil { + st = append(st, node.Right) + } + if node.Left != nil { + st = append(st, node.Left) + } + } else { + st = st[:len(st)-1] + node = st[len(st)-1] + st = st[:len(st)-1] + depth-- + } + if result < depth { + result = depth + } + } + return result +} +``` + ### JavaScript: 递归法: