1. BinaryGap

using System;
using System.Collections.Generic;
using System.Linq;

class Solution {
    public int solution(int N) {
     string bin = Convert.ToString(N, 2);
     //Console.WriteLine(bin);
     int gap    = 0;
     int maxGap = 0 ;
     for (int i = 0; i < bin.Length; i++){
        if (bin[i] == '1'){ 
            if (gap > maxGap){
                 maxGap = gap;
                }
             gap = 0;
            }
             else {
                gap++;
          }
        }
     return maxGap;
    }
}