[doh6077] WEEK 01 solutions

contains-duplicate/doh6077.py

@@ -1,10 +1,7 @@
+# https://leetcode.com/problems/contains-duplicate/description/
 
-# set에 저장하면서 중복 여부 확인하기
 class Solution:
-    def containsDuplicate(self, nums: list[int]) -> bool:
-        hashset = set()
-        for i in nums:
-            if i in hashset:
-                return True
-            hashset.add(i)
-        return False
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        # Create a set to store unique numbers from nums
+        nums_set = set(nums)
+        return len(nums_set) != len(nums)

two-sum/doh6077.py

@@ -1,8 +1,24 @@
+# 6기 
+# class Solution:
+#     def twoSum(self, nums: list[int], target: int) -> list[int]:
+#         prevMap = {} # val : index 
+#         for i, n in enumerate(nums):
+#             diff = target - n 
+#             if diff in prevMap:
+#                 return [prevMap[diff], i]
+#             prevMap[n] = i 
+
+# 7기 
+# https://leetcode.com/problems/two-sum/description/
 class Solution:
-    def twoSum(self, nums: list[int], target: int) -> list[int]:
-        prevMap = {} # val : index 
-        for i, n in enumerate(nums):
-            diff = target - n 
-            if diff in prevMap:
-                return [prevMap[diff], i]
-            prevMap[n] = i 
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        # use Hash map to save num and index 
+        nums_hm = {}
+
+        for i, num in enumerate(nums):
+            find_val = target - num
+
+            if find_val in nums_hm:
+                return [nums_hm[find_val], i]
+
+            nums_hm[num] = i