两数之和 - 简书

例如，切片[12,16,34,4,9,6,21]，target=38,求切片对应的下标？

package main

import "fmt"

func twoSum(nums []int, target int) []int {
    recordMap := make(map[int]int)
    resultArray := make([]int, 0)
    for k, v := range nums {
        if _, s := recordMap[target-v]; s {
            resultArray = append(resultArray, recordMap[target-v])
            resultArray = append(resultArray, k)
        }
        recordMap[v] = k
    }
    return resultArray
}
func main() {
    num := []int{12,16,34,4,9,6,21}
    fmt.Println(twoSum(num, 38))

}



[2 3]

大概的思路是：
target不断的和切片中的每个元素相减，然后再去匹配相减后的结果是否在切片中。时间复杂度为O(n)