Add week 13 solutions: lowest-common-ancestor-of-a-binary-search-tree

Author: gitsunmin

lowest-common-ancestor-of-a-binary-search-tree/gitsunmin.ts

@@ -0,0 +1,25 @@
+/**
+ * https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/
+ * time complexity : O(log n)
+ * space complexity : O(1)
+ */
+
+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 lowestCommonAncestor(root: TreeNode | null, p: TreeNode, q: TreeNode): TreeNode | null {
+    while (root) {
+        if (p.val < root.val && q.val < root.val) root = root.left;
+        else if (p.val > root.val && q.val > root.val) root = root.right;
+        else return root;
+    }
+    return null;
+};