LeetCode:ReverseBits

Problem:

https://leetcode.com/problems/reverse-bits/

My brute force solutions get accepted,the algorithm is to push all the remainders into a stack and then multiplying each bit with corresponding power of 2

#include<bits/stdc++.h>
using namespace std;
class Solution {
public:
 int reverseBits(int n) 
 {
         int x=1,i=0;
  long long res=0;
  stack<int>st;
  while(x<=32)
  {
   st.push(abs(n%2));
   n>>=1;
   x++;
  }
  res=0;
  while(!st.empty())
  { 
   res+=(st.top()*(pow(2,i)));
   i++;
   st.pop();
  }
  return res;
   }
};

Reference :

Here

Method 2

#include<bits/stdc++.h>
#define INT_SIZE 32
using namespace std;
class Solution 
{
 public:
 int reverseBits(unsigned int num)
 {
  int i=INT_SIZE-1;
  unsigned int rev_num=0;
  while(i>=0 && num)
  {
   if(num & 1)
   rev_num |= (1<<i);
   num>>=1;
   i--;
  }
 return rev_num;
 }
};
int main()
{
 Solution s;
 cout<<s.reverseBits(8)<<endl;
}