diff --git a/1.two-sum.ts b/1.two-sum.ts
new file mode 100644
index 0000000..d30d053
--- /dev/null
+++ b/1.two-sum.ts
@@ -0,0 +1,19 @@
+// @leet start
+function twoSum(nums: number[], target: number): number[] {
+	const m: Map<number, number> = new Map();
+
+	for (let index = 0; index < nums.length; index++) {
+		const item = nums[index];
+		const resInMap = m.get(item);
+		if (resInMap !== undefined) {
+			console.log("early stopping");
+			return [resInMap, index];
+		} else {
+			const res = target - item;
+			m.set(res, index);
+		}
+	}
+
+	return [];
+}
+// @leet end