Create Solution.java

Author: Jerring

solution/0450.Delete Node in a BST/Solution.java

@@ -0,0 +1,29 @@
+class Solution {
+    public TreeNode deleteNode(TreeNode root, int key) {
+        if (root == null) {
+            return null;
+        }
+        if (root.val > key) {
+            root.left = deleteNode(root.left, key);
+            return root;
+        } else if (root.val < key) {
+            root.right = deleteNode(root.right, key);
+            return root;
+        } else {
+            if (root.left == null) return root.right;
+            if (root.right == null) return root.left;
+            TreeNode newRoot = root.right;
+            TreeNode parent = null;
+            while (newRoot.left != null) {
+                parent = newRoot;
+                newRoot = newRoot.left;
+            }
+            if (parent != null) {
+                parent.left = newRoot.right;
+                newRoot.right = root.right;
+            }
+            newRoot.left = root.left;
+            return newRoot;
+        }
+    }
+}