2024-08-22 13:00
Status: child
Tags: Leetcode leetcode two-pointers leetcode-medium Two Sum
Two Sum II
Code
class Solution(object):
def twoSum(self, numbers, target):
"""
:type numbers: List[int]
:type target: int
:rtype: List[int]
"""
# initializes the left and right pointers
l, r = 0, len(numbers) - 1
# sets up the loop
while l < r:
curSum = numbers[l] + numbers[r]
if curSum > target:
r-= 1
elif curSum < target:
l += 1
else:
return [l + 1, r + 1]Explanation
List: [1, 3, 4, 5, 7, 11] Target: 9
1st Loop
- numbers[l] = 1
- numbers[r] = 11
- curSum = 12
- since the sum > target, we shift the right pointer to the left, essentially decreasing it(if curSum > target
2nd Loop
- numbers[l] = 1
- numbers[r] = 7
- curSum = 8
- since the sum < target, we shift the left pointer to the right, essentially increasing it(if curSum < target
3rd Loop
- numbers[l] = 3
- numbers[r] = 7
- curSum = 10
- since the sum > target, we shift the right pointer to the left, essentially decreasing it(if curSum > target
4th Loop
- numbers[l] = 3
- numbers[r] = 5
- curSum = 8
- since the sum < target, we shift the left pointer to the right, essentially increasing it(if curSum < target
5th Loop
- numbers[l] = 4
- numbers[r] = 5
- curSum = 9
- return the indexes