feat: reverse bits

Author: minji-go

reverse-bits/minji-go.java

@@ -0,0 +1,19 @@
+/*
+    Problem: https://leetcode.com/problems/reverse-bits/
+    Description: Reverse bits of a given 32 bits unsigned integer
+    Topics: Divide and Conquer, Bit Manipulation
+    Time Complexity: O(1), Runtime 1ms
+    Space Complexity: O(1), Memory 41.72MB
+*/
+public class Solution {
+    public int reverseBits(int n) {
+        long unsignedNum = n > 0 ? n : n + 2 * (long) Math.pow(2,31); //= Integer.toUnsignedLong()
+
+        int reversedNum = 0;
+        for(int i=31; i>=0; i--){
+            if(unsignedNum % 2 == 1) reversedNum += (long) Math.pow(2,i); //= (1<<i)
+            unsignedNum/=2;
+        }
+        return reversedNum;
+    }
+}