Binary String with Substrings Representing 1 to N in C++

Suppose we have a binary string S and a positive integer N, we have to say true if and only if for every integer X from 1 to N, the binary representation of X is a substring of the given S. So if S = “0110” and N = 3, then the result will be true, as 1, 10 and 11 all are present in 0110.

To solve this, we will follow these steps −

• Define a method to convert(), that will take n as input

• ret := an empty string

• while n is not 0

  • ret := ret concatenate n mod 2

  • n := n / 2

• reverse ret and return

• From the main method, do the following

• for i := N, when i >= N/2, decrease i by 1

  • temp := convert(i)

  • if temp is not in S, return false

• return true.

Let us see the following implementation to get better understanding −

Example

 Live Demo

#include <bits/stdc++.h>
using namespace std;
class Solution {
   public:
   string convert(int n){
      string ret = "";
      while(n){
         ret += (n % 2) + '0';
         n /= 2;
      }
      reverse(ret.begin(), ret.end());
      return ret;
   }
   bool queryString(string S, int N) {
      for(int i = N; i >= N/2; i-- ){
         string temp = convert(i);
         if(S.find(temp) == string::npos) return false;
      }
      return true;
   }
};
main(){
   Solution ob;
   cout << (ob.queryString("0110", 3));
}

Input

"0110"
3

Output

1