给定 nums = [2, 7, 11, 15], target = 9

因为 nums[0] + nums[1] = 2 + 7 = 9

所以返回 [0, 1]

leetCode 给出运行时间 60ms

func twoSum(nums []int, target int) []int {

	for i := 0; i < len(nums)-1; i++ {

		for j := i+1; j < len(nums); j++ {

			if nums[i]+nums[j] == target {

				return []int{nums[i], nums[j]}

			}

		}

	}

	return nil

}

leetCode 给出运行时间 8ms

package main

import "fmt"

func main(){

	nums := []int{3,3}

	fmt.Println(twoSum(nums,6))

}

func twoSum(nums []int, target int) []int {

	numsMap := make(map[int]int)

	for i := 0; i < len(nums); i++ {

		numsMap[nums[i]] = i

	}

	for i := 0; i < len(nums); i++ {

		if _,ok := numsMap[target-nums[i]];ok && numsMap[target-nums[i]] != i{

			return []int{numsMap[target-nums[i]], i}

		}

	}

	return nil

}