diff --git a/problems/0101.对称二叉树.md b/problems/0101.对称二叉树.md index e4e232c8..97ca0685 100644 --- a/problems/0101.对称二叉树.md +++ b/problems/0101.对称二叉树.md @@ -725,5 +725,25 @@ func isSymmetric3(_ root: TreeNode?) -> Bool { } ``` +## Scala + +递归: +```scala +object Solution { + def isSymmetric(root: TreeNode): Boolean = { + if (root == null) return true // 如果等于空直接返回true + def compare(left: TreeNode, right: TreeNode): Boolean = { + if (left == null && right == null) return true // 如果左右都为空,则为true + if (left == null && right != null) return false // 如果左空右不空,不对称,返回false + if (left != null && right == null) return false // 如果左不空右空,不对称,返回false + // 如果左右的值相等,并且往下递归 + left.value == right.value && compare(left.left, right.right) && compare(left.right, right.left) + } + // 分别比较左子树和右子树 + compare(root.left, root.right) + } +} +``` + -----------------------