[WHYjun] WEEK 02 solutions - (4/5)

Author: WHYjun

3sum/WHYjun.py

@@ -0,0 +1,30 @@
+class Solution:
+    def threeSum(self, nums: List[int]) -> List[List[int]]:
+        answer = []
+        sortedNums = sorted(nums)
+
+        for i in range(len(sortedNums)):
+            # skip if same to avoid dup
+            if i > 0 and sortedNums[i] == sortedNums[i-1]:
+                continue
+
+            # use two pointers
+            j = i + 1
+            k = len(sortedNums) - 1
+
+            while j < k:
+                total = sortedNums[i] + sortedNums[j] + sortedNums[k]
+
+                if total == 0:
+                    answer.append([sortedNums[i], sortedNums[j], sortedNums[k]])
+                    j += 1
+                    # skip if same to avoid dup
+                    while sortedNums[j] == sortedNums[j-1] and j < k:
+                        j += 1
+                elif total < 0:
+                    j += 1
+                else:
+                    k -= 1
+
+        return answer
+