3sum solution

Author: yuseok89

3sum/yuseok89.py

@@ -0,0 +1,33 @@
+# TC: O(N^2)
+# SC: O(N)
+class Solution:
+    def threeSum(self, nums: list[int]) -> list[list[int]]:
+
+        cnt_dict = Counter(nums)
+        nums_uniq = sorted(cnt_dict.keys())
+        n = len(nums_uniq)
+
+        ret = []
+
+        for num in cnt_dict.keys():
+            if num == 0:
+                if cnt_dict[num] >= 3:
+                    ret.append([0, 0, 0])
+            elif cnt_dict[num] >= 2 and num * 2 * -1 in cnt_dict:
+                ret.append([num, num, num * 2 * -1])
+
+        for idx1, num1 in enumerate(nums_uniq):
+            if num1 > 0:
+                break
+
+            for idx2 in range(idx1 + 1, n):
+                num2 = nums_uniq[idx2]
+                num3 = (num1 + num2) * -1
+
+                if num2 >= num3:
+                    break
+                elif num3 in cnt_dict:
+                    ret.append([num1, num2, num3])
+
+        return ret
+

product-of-array-except-self/yuseok89.py

@@ -1,5 +1,5 @@
-// TC: O(N)
-// SC: O(N)
+# TC: O(N)
+# SC: O(N)
 class Solution:
     def productExceptSelf(self, nums: List[int]) -> List[int]: