add twosum solution

go/1-Two-Sum.go

@@ -0,0 +1,12 @@
+package main
+
+func twoSum(nums []int, target int) []int {
+ prevMap := make(map[int]int)
+ for i, num := range nums {
+ if j, ok := prevMap[target-num]; ok {
+ return []int{j, i}
+ }
+ prevMap[num] = i
+ }
+ return []int{}
+}