BinaryGap.java

package BinaryGap;

class Solution {
    public int solution(int N) {
        // write your code in Java SE 8
        
        int max_gap = 0;
        int current_gap =0;
        boolean counting = false; 
        
        // Using the "concept of bit manipulation" and "& operation"
        
        while( N !=0 ){
        
            if(counting == false){    // for the first "1"   
                if( (N&1) == 1){      // note: cannot use n&1 withoug "()"
                    counting = true;  // start to count
                }
            }
            else{                    // counting = true
                if( (N&1) ==0){      // note: cannot use n&1 withoug "()"
                    current_gap ++;  
                }
                else{ // N & 1 == 1
                    max_gap = Math.max(max_gap, current_gap);
                    current_gap = 0; // reset
                }
            }
            
            N = N >> 1; // shift by one (right side) 
                        // note: cannot just write "N >> 1"
        }
        
        return max_gap;
    }
}