Program to find longest consecutive run of 1 in binary form of a number in C++

Suppose we have a number n, we have to find the length of the longest consecutive run of 1s in its binary representation.

So, if the input is like n = 312, then the output will be 3, as 312 is 100111000 in binary and there are 3 consecutive 1s.

To solve this, we will follow these steps −

• ret := 0, len := 0

• for initialize i := 0, when i < 32, update (increase i by 1), do:

  • if n/2 is odd, then

    • (increase len by 1)

  • Otherwise

    • len := 0

  • ret := maximum of ret and len

• return ret

Let us see the following implementation to get better understanding:

Source Code (C++) −

Example

#include <bits/stdc++.h>
using namespace std;
class Solution {
   public:
   int solve(int n) {
      int ret = 0;
      int len = 0;
      for(int i = 0; i < 32; i++){
         if((n >> i) & 1){
            len++;
         }else{
            len = 0;
         }
         ret = max(ret, len);
      }
      return ret;
   }
};
main(){
   Solution ob;
   cout << ob.solve(312);
}

Input

312

Output

3