# Leetcode - 167. Two Sum II - Input array is sorted

## 풀이

브루트 포스

class Solution:
def twoSum(self, numbers: List[int], target: int) -> List[int]:
for idx1, num1 in enumerate(numbers):
for idx2, num2 in enumerate(numbers[idx1 + 1 :]):
if num1 + num2 > target:
break
if num1 + num2 == target:
return sorted([idx1 + 1, idx1 + idx2 + 2])

Binary search

class Solution:
def twoSum(self, numbers: List[int], target: int) -> List[int]:
for idx, num in enumerate(numbers):
new_target = target - num

left, right = idx + 1, len(numbers) - 1
while left <= right:
mid = (left + right) // 2

if numbers[mid] < new_target:
left = mid + 1
elif numbers[mid] > new_target:
right = mid - 1
else:
return [idx + 1, mid + 1]

Two pointers

class Solution:
def twoSum(self, numbers: List[int], target: int) -> List[int]:
left, right = 0, len(numbers) - 1
while left != right:
if numbers[left] + numbers[right] < target:
left += 1
elif numbers[left] + numbers[right] > target:
right -= 1
else:
return [left + 1, right + 1]