binaryGap_solution.js

/* 
  @description function for determining Binary Gap in binary numbers,
  inspired by a codility test
*/
 
function BinaryGap(N) {
  
	var bin = N.toString(2);
  //console.log(`We have been fed ${bin}`);
	
	var lastIndex = 0;
	var currentArr, highestArr = [];
	var repeatCheck = 0;
	//create an array that contains the right solution set (i.e. has the longest number of zeros)
	for (var i=0; i<bin.length; i++) {
		if( bin[i] === '0' ) {
			//use repeatCheck as flag for when '0' follows another '0'
			repeatCheck++;
			var j;
			if (repeatCheck>1) {
				j =  bin.slice(lastIndex, i+1);
				//Add a 0 to the currentArr since its still has a 0 that we didnt catch
				j = currentArr+'0';
			} else {
				j =  bin.slice(lastIndex, i+1);
			}
			//save the current solution
			currentArr = j;
			//increase index number for the lastIndex visited
			lastIndex = i+1;
			//compare if the currentArr is higher in length by our record highest
			if (currentArr.length > highestArr.length) {
				highestArr = currentArr;
			}
		} else {
			//reset repeatCheck here since a 1 has been encountered
			repeatCheck = 0;
		}
	}
	
	var filter = Array.prototype.filter;
	var findZeros = filter.call(highestArr, function (x){
		if(x === '0') {
			return x;
		}
	});
	
	//return ZeroCount;
	return findZeros.length;
	
}


var result = BinaryGap(bin);
console.log(`BinaryGap is ${result}`);