Add Two Sum solution in TypeScript

Author: Jeehay28

two-sum/Jeehay28.ts

@@ -0,0 +1,42 @@
+// Approach 2: HashMap (Using Map in TypeScript)
+// ⏳ Time Complexity: O(n) ✅ (Efficient for large inputs)
+// 💾 Space Complexity: O(n) ❌ (Extra memory used for Map)
+
+function twoSum(nums: number[], target: number): number[] {
+
+    const indices = new Map<number, number>();
+
+    for (let i = 0; i < nums.length; i++) {
+
+        const temp = target - nums[i];
+        if (indices.has(temp)) {
+            // Ensure correct order
+            return [indices.get(temp)!, i];
+            // The exclamation mark (!) in indices.get(temp)! is a non-null assertion operator in TypeScript.
+        }
+        // If you return [i, indices.get(temp)!], 
+        // you would be returning the current index first, 
+        // which is incorrect because the problem statement usually expects indices in the order they were found (earlier index first).
+
+        indices.set(nums[i], i);
+    }
+    return [];
+};
+
+
+// Approach 1: Brute Force (O(n^2))
+// ⏳ Time Complexity: O(n^2) ❌ (Inefficient for large inputs)
+// 💾 Space Complexity: O(1) ✅ (Great, no extra memory used!)
+
+// function twoSum(nums: number[], target: number): number[] {
+//     for (let i = 0; i < nums.length; i++) {
+//         for (let j = i + 1; j < nums.length; j++) {
+//             if (nums[i] + nums[j] === target) {
+//                 return [i, j]
+//             }
+//         }
+//     }
+//     return [];
+// };
+
+