Refactored solution 101

Author: brenobaptista

leetcode/0101.Symmetric-Tree/101. Symmetric Tree.go

@@ -16,51 +16,22 @@ type TreeNode = structures.TreeNode
  * }
  */
 
-// 解法一 dfs
-func isSymmetric(root *TreeNode) bool {
-	return root == nil || dfs(root.Left, root.Right)
-}
-
-func dfs(rootLeft, rootRight *TreeNode) bool {
-	if rootLeft == nil && rootRight == nil {
+func isMirror(left *TreeNode, right *TreeNode) bool {
+	if left == nil && right == nil {
 		return true
 	}
-	if rootLeft == nil || rootRight == nil {
-		return false
-	}
-	if rootLeft.Val != rootRight.Val {
+
+	if left == nil || right == nil {
 		return false
 	}
-	return dfs(rootLeft.Left, rootRight.Right) && dfs(rootLeft.Right, rootRight.Left)
-}
 
-// 解法二
-func isSymmetric1(root *TreeNode) bool {
-	if root == nil {
-		return true
-	}
-	return isSameTree(invertTree(root.Left), root.Right)
+	return (left.Val == right.Val) && isMirror(left.Left, right.Right) && isMirror(left.Right, right.Left)
 }
 
-func isSameTree(p *TreeNode, q *TreeNode) bool {
-	if p == nil && q == nil {
+func isSymmetric(root *TreeNode) bool {
+	if root == nil {
 		return true
-	} else if p != nil && q != nil {
-		if p.Val != q.Val {
-			return false
-		}
-		return isSameTree(p.Left, q.Left) && isSameTree(p.Right, q.Right)
-	} else {
-		return false
 	}
-}
 
-func invertTree(root *TreeNode) *TreeNode {
-	if root == nil {
-		return nil
-	}
-	invertTree(root.Left)
-	invertTree(root.Right)
-	root.Left, root.Right = root.Right, root.Left
-	return root
+	return isMirror(root.Left, root.Right)
 }