binaryCountMax.js

// 'Find longest sequence of zeros in binary representation of an integer.'

function dec2bin(n) {
  return parseInt(n, 10).toString(2)
}

function findIntervals(arrBin, intervals) {
  // '1101100011001110110'
  let firstIndex = arrBin.indexOf('1')
  //0
  let remainPart = arrBin.slice(firstIndex + 1)
  // '101100011001110110'
  let secondIndex = remainPart.indexOf('1')
  if (secondIndex > -1) {
    if (secondIndex !== 0) {
      intervals.push(secondIndex)
    }
    let willRemainPart = remainPart.slice(secondIndex)
    if (willRemainPart.length > 0) {
      findIntervals(willRemainPart, intervals)
    }
  }
  return intervals
}

function findMax(X) {
  if (Number.isInteger(X)) {
    const binaryX = dec2bin(X)
    const intervalArr = findIntervals(binaryX,[])
    return (intervalArr.length>0) ? Math.max.apply(Math,intervalArr) : 0
  }
}

const x = 51712
const cc = findMax(x)
console.log(cc)