create: 0450-delete-node-in-a-bst.ts

Author: fahim041

typescript/0450-delete-node-in-a-bst.ts

@@ -0,0 +1,44 @@
+/**
+ * Definition for a binary tree node.
+ * class TreeNode {
+ *     val: number
+ *     left: TreeNode | null
+ *     right: TreeNode | null
+ *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
+ *         this.val = (val===undefined ? 0 : val)
+ *         this.left = (left===undefined ? null : left)
+ *         this.right = (right===undefined ? null : right)
+ *     }
+ * }
+ */
+
+function deleteNode(root: TreeNode | null, key: number): TreeNode | null {
+    if (!root) {
+        return root;
+    }
+
+    if (key > root.val) {
+        root.right = deleteNode(root.right, key);
+    } else if (key < root.val) {
+        root.left = deleteNode(root.left, key);
+    } else {
+        if (!root.right) {
+            return root.left;
+        } else if (!root.left) {
+            return root.right;
+        } else {
+            let minNode = minValueNode(root.right);
+            root.val = minNode.val;
+            root.right = deleteNode(root.right, minNode.val);
+        }
+    }
+    return root;
+}
+
+function minValueNode(root: TreeNode): TreeNode {
+    let curr: TreeNode = root;
+    while (curr && curr.left) {
+        curr = curr.left;
+    }
+    return curr;
+}