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authorJack Sangdahl <[email protected]>2024-12-13 18:15:06 -0700
committerJack Sangdahl <[email protected]>2024-12-13 18:15:06 -0700
commit6454a6e0421beab63ae3eacb584ef68b9dbac564 (patch)
treedbb6447066ea2b078d7ab7781aa25be9ff7291af /3sum.py
parentcbd2047ff2a47ab0cfe13b8b9473d5039d488ddc (diff)
downloadleetcode-6454a6e0421beab63ae3eacb584ef68b9dbac564.tar.gz
leetcode-6454a6e0421beab63ae3eacb584ef68b9dbac564.zip
15. 3sum
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+# 15. 3Sum
+
+"""
+given an integer array 'nums', return all the triplets '[nums[i], nums[j],
+nums[k]]' such that 'i != j', 'i != k', 'j != k', and 'nums[i] + nums[j] +
+nums[k] == 0'. notice that the solution set must not contain duplicate
+triplets
+"""
+
+
+class Solution:
+ def threeSum(self, nums):
+ """
+ :type nums: List[int]
+ :rtype: List[List[int]]
+ """
+ nums.sort()
+ ans = []
+ if len(nums) < 3:
+ return ans
+ for i in range(len(nums)):
+ if nums[i] > 0:
+ break
+ if i > 0 and nums[i] == nums[i - 1]:
+ continue
+ j, k = i + 1, len(nums) - 1
+ while j < k:
+ total_sum = nums[i] + nums[j] + nums[k]
+ if total_sum > 0:
+ k -= 1
+ elif total_sum < 0:
+ j += 1
+ else:
+ ans.append([nums[i], nums[j], nums[k]])
+ prev_j, prev_k = nums[j], nums[k]
+ while j < k and nums[j] == prev_j:
+ j += 1
+ while j < k and nums[k] == prev_k:
+ k -= 1
+ return ans
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ print(obj.threeSum(nums=[-1, 0, 1, 2, -1, -4]))
+ print(obj.threeSum(nums=[0, 1, 1]))
+ print(obj.threeSum(nums=[0, 0, 0]))