Merge pull request neetcode-gh#2372 from ksfkwan/patch-1

Update 0015-3sum.py

python/0015-3sum.py

@@ -1,27 +1,27 @@
 class Solution:
- def threeSum(self, nums: List[int]) -> List[List[int]]:
- res = []
- nums.sort()
-
- for i, a in enumerate(nums):
- # Skip positive integers
- if a > 0:
+ def ThreeSum(self, integers):
+ """
+ :type integers: List[int]
+ :rtype: List[List[int]]
+ """
+ integers.sort()
+ result = []
+ for index in range(len(integers)):
+ if integers[index] > 0:
  break
-
- if i > 0 and a == nums[i - 1]:
+ if index > 0 and integers[index] == integers[index - 1]:
  continue
-
- l, r = i + 1, len(nums) - 1
- while l < r:
- threeSum = a + nums[l] + nums[r]
- if threeSum > 0:
- r -= 1
- elif threeSum < 0:
- l += 1
+ left, right = index + 1, len(integers) - 1
+ while left < right:
+ if integers[left] + integers[right] < 0 - integers[index]:
+ left += 1
+ elif integers[left] + integers[right] > 0 - integers[index]:
+ right -= 1
  else:
- res.append([a, nums[l], nums[r]])
- l += 1
- r -= 1
- while nums[l] == nums[l - 1] and l < r:
- l += 1
- return res
+ result.append([integers[index], integers[left], integers[right]]) # After a triplet is appended, we try our best to incease the numeric value of its first element or that of its second.
+ left += 1 # The other pairs and the one we were just looking at are either duplicates or smaller than the target.
+ right -= 1 # The other pairs are either duplicates or greater than the target.
+ # We must move on if there is less than or equal to one integer in between the two integers.
+ while integers[left] == integers[left - 1] and left < right:
+ left += 1 # The pairs are either duplicates or smaller than the target.
+ return result