feat: week3 easy 문제 풀이

Author: jinah92

reverse-bits/jinah92.py

@@ -0,0 +1,14 @@
+# O(1) time, O(1) space
+class Solution:
+    def reverseBits(self, n: int) -> int:
+        stack = []
+        while len(stack) < 32:
+            stack.append(n % 2)
+            n //=2
+        
+        result, scale = 0, 1
+        while stack:
+            result += stack.pop() * scale
+            scale *= 2
+        
+        return result

two-sum/jinah92.py

@@ -0,0 +1,12 @@
+# O(n) time, O(n) space
+
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        num_set = {}
+        
+        for idx, num in enumerate(nums):
+            other_num = target - num
+            if other_num in num_set:
+                return [idx, num_set[other_num]]
+            else:
+                num_set[num] = idx