alg-3n-1.js

// Veja mais em: https://www.youtube.com/watch?v=voV5OBCqlVs

function cycleLen(n){
  let steps = 1
  while(n !== 1){
    if ( n % 2 === 0){
      n = n / 2
    }else{
      n = 3 * n + 1
    }
    steps++
  }
  return steps
}

function maxCycle(i,j){
  let max = cycleLen(i)
  for (let k = i + 1; k <= j; k++) {
    let currentCycle = cycleLen(k)
    if (currentCycle > max) {
      max = currentCycle
    }
  }
  return i+' '+j+' '+max
}

console.log(maxCycle(1,10))
console.log(maxCycle(100,200))
console.log(maxCycle(201,210))
console.log(maxCycle(900,1000))