feat(1-two-sum): add golang best soln

0001_two-sum/golang/two-sum-best-approach.go

@@ -0,0 +1,14 @@
+func twoSum(nums []int, target int) []int {
+	// Optimal solution: using a hashtable
+	m := make(map[int]int)
+
+	for i, num := range nums {
+		if j, ok := m[target-num]; ok {
+			return []int{i, j}
+		}
+
+		m[num] = i
+	}
+
+	return []int{}
+}