문제
Given a 1-indexed array of integers numbers that is already sorted in non-decreasing order, find two numbers such that they add up to a specific target number. Let these two numbers be numbers[index1] and numbers[index2] where 1 <= index1 < index2 <= numbers.length.
Return the indices of the two numbers, index1 and index2, added by one as an integer array [index1, index2] of length 2.
The tests are generated such that there is exactly one solution. You may not use the same element twice.
Your solution must use only constant extra space.
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. We return [1, 2].
Example 2:
Input: numbers = [2,3,4], target = 6
Output: [1,3]
Explanation: The sum of 2 and 4 is 6. Therefore index1 = 1, index2 = 3. We return [1, 3].
오름차순으로 정렬된 배열에서 두 개의 요소를 더했을 때 target 값과 같으면 그 요소들의 인덱스를 배열로 반환하라고 한다.
처음에 중첩 for문으로 작성했더니 시간초과 떠서 opposite direction로 다시 작성했다.
class Solution:
def twoSum(self, numbers: List[int], target: int) -> List[int]:
left = 0
right = len(numbers)-1
while(left < right):
if(numbers[left]+numbers[right] > target):
right -= 1
elif(numbers[left]+numbers[right] < target):
left += 1
else:
return list([left+1,right+1])