fd

Author: dingjikerbo

README.md

@@ -379,6 +379,7 @@
 |547|[Friend Circles](https://leetcode.com/problems/friend-circles/)|[Java](leetcode/solution/src/FriendCircles.java)|70||
 |557|[Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii/)| [Java](leetcode/solution/src/ReverseWordsInAStringIII.java)|100||
 |560|[Subarray Sum Equals K](https://leetcode.com/problems/subarray-sum-equals-k/)| [Java](leetcode/solution/src/SubarraySumEqualsK.java)|70||
+|563|[Binary Tree Tilt](https://leetcode.com/problems/binary-tree-tilt/)|[Java](leetcode/solution/src/BinaryTreeTilt.java)|90||
 |564|[Find the Closest Palindrome](https://leetcode.com/problems/find-the-closest-palindrome/)|[Java](leetcode/solution/src/FindTheClosestPalindrome.java)|80|此题暴力法即可|
 |572|[Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree/)|[Java](leetcode/solution/src/SubtreeOfAnotherTree.java)|80||
 |606|[Construct String from Binary Tree](https://leetcode.com/problems/construct-string-from-binary-tree/)|[Java](leetcode/solution/src/ConstructStringFromBinaryTree.java)|90||

leetcode/solution/src/BinaryTreeTilt.java

@@ -0,0 +1,19 @@
+public class BinaryTreeTilt {
+
+    int tilt = 0;
+
+    public int findTilt(TreeNode root) {
+        helper(root);
+        return tilt;
+    }
+
+    private int helper(TreeNode root) {
+        if (root == null) {
+            return 0;
+        }
+        int left = helper(root.left);
+        int right = helper(root.right);
+        tilt += Math.abs(left - right);
+        return left + right + root.val;
+    }
+}

leetcode/src/Main.java

@@ -6,18 +6,21 @@ public class Main {
 
     public static class Solution {
 
-        public boolean isSubtree(TreeNode s, TreeNode t) {
-            return isEqual(s, t) || (s != null && (isSubtree(s.left, t) || isSubtree(s.right, t)));
+        int tilt = 0;
+
+        public int findTilt(TreeNode root) {
+            helper(root);
+            return tilt;
         }
 
-        private boolean isEqual(TreeNode s, TreeNode t) {
-            if (t == null && s == null) {
-                return true;
-            }
-            if (t == null || s == null) {
-                return false;
+        private int helper(TreeNode root) {
+            if (root == null) {
+                return 0;
             }
-            return s.val == t.val && isEqual(s.left, t.left) && isEqual(s.right, t.right);
+            int left = helper(root.left);
+            int right = helper(root.right);
+            tilt += Math.abs(left - right);
+            return left + right + root.val;
         }
     }