110 finish. 19ms.

Author: aQua

Algorithms/0110.balanced-binary-tree/balanced-binary-tree.go

@@ -7,6 +7,29 @@ import (
 type TreeNode = kit.TreeNode
 
 func isBalanced(root *TreeNode) bool {
+	_, isBalanced := cur(root)
+	return isBalanced
+}
+
+func cur(root *TreeNode) (int, bool) {
+	if root == nil {
+		return 0, true
+	}
+
+	leftDeepth, leftIsBalanced := cur(root.Left)
+	rightDeepth, rightIsBalanced := cur(root.Right)
+
+	if leftIsBalanced && rightIsBalanced &&
+		-1 <= leftDeepth-rightDeepth  && leftDeepth - rightDeepth <= 1 {
+		return max(leftDeepth, rightDeepth) + 1, true
+	}
+
+	return 0, false
+}
 
-	return true 
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
 }