LeetCodeに毎日挑戦してみた 167. Two Sum II - Input array is sorted（Python、Go）

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37問目（問題167)

167. Two Sum II - Input array is sorted

問題内容

• 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 1:

  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.

Example 2:

  Input: numbers = [2,3,4], target = 6
  Output: [1,3]

Example 3:

  Input: numbers = [-1,0], target = -1
  Output: [1,2]

考え方

1. numbersの数だけループを回します

2. dicに値を格納していき、target-numが存在したら終了します

解答コード

def twoSum(self, numbers, target):
    dic = {}
    for i, num in enumerate(numbers):
        if target-num in dic:
            return [dic[target-num]+1, i+1]
        dic[num] = i

• Goでも書いてみます！

func twoSum(numbers []int, target int) []int {
    m := make(map[int]int)
    for i := 0; i < len(numbers); i++ {
        idx, ok := m[target-numbers[i]]
        if ok {
            return []int{idx + 1, i + 1}
        }
        m[numbers[i]] = i
    }
    return nil
}