99. Recover Binary Search Tree (java)

Author: bluesword12350

solution/0099.Recover Binary Search Tree/Solution.java

@@ -0,0 +1,19 @@
+class Solution {
+    private TreeNode first,second,pre;
+    public void recoverTree(TreeNode root) {
+        traverse(root);
+        int temp = first.val;
+        first.val = second.val;
+        second.val = temp;
+    }
+    private void traverse(TreeNode root) {
+        if (root == null) return;
+        traverse(root.left);
+        if (pre != null) {
+            if (first == null && pre.val > root.val) first = pre;
+            if (first != null && pre.val > root.val) second = root;
+        }
+        pre = root;
+        traverse(root.right);
+    }
+}