167. Two Sum II - Input array is sorted

Description

Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2.

Note:

Your returned answers (both index1 and index2) are not zero-based.
You may assume that each input would have exactly one solution and you may not use the same element twice.
Example:

Input: numbers = [2,7,11,15], target = 9
Output: [1,2]
Explanation: The sum of 2 and 7 is 9. Therefore index1 = 1, index2 = 2.

Answer

package main

import "fmt"

func twoSum(numbers []int, target int) []int {
    tempmap := make(map[int]int)
    for i := 0; i < len(numbers); i++ {
        tempmap[numbers[i]] = i + 1
    }

    ret := 0
    resp := make([]int, 2)
    for i := 0; i < len(numbers); i++ {
        ret = target - numbers[i]
        resp[0] = i + 1
        if v, ok := tempmap[ret]; ok {
            resp[1] = v
            break
        }
    }

    return resp
}

func main() {
    fmt.Println(twoSum([]int{2, 7, 3, 8}, 9))
}