solve(w08): 190. Reverse Bits

Author: seungriyou

reverse-bits/seungriyou.py

@@ -0,0 +1,32 @@
+# https://leetcode.com/problems/reverse-bits/
+
+class Solution:
+    def reverseBits_32(self, n: int) -> int:
+        """
+        [Complexity]
+            - TC: O(32)
+            - SC: O(1)
+
+        [Approach]
+            n의 맨 오른쪽 bit부터 res의 맨 왼쪽에 붙여나가기
+        """
+        res = 0
+        for i in range(32):
+            res |= ((n >> i) & 1) << (31 - i)
+        return res
+
+    def reverseBits(self, n: int) -> int:
+        """
+        [Complexity]
+            - TC: O(16)
+            - SC: O(1)
+
+        [Approach]
+            n의 바깥쪽에서부터 two pointer 처럼 res에 모으기
+        """
+        res = 0
+        for i in range(16):
+            left = (n >> (31 - i)) & 1
+            right = (n >> i) & 1
+            res |= (left << i) | (right << (31 - i))
+        return res