leetcode-659.js

var isPossible = function(nums) {
  if (nums.length === 0) return true
  if (nums.length < 3) return false
  
  const clone = [...nums.slice(1)]
  const seq = [nums[0]]
  for (let i=0; i < nums.length && seq.length < 3; i++) {
    const next = seq[seq.length - 1] + 1
    if (nums[i] === next) {
      clone.splice(i-seq.length, 1)
      seq.push(nums[i])
    }
  }
  
  if (seq.length < 3) return false
  if (isPossible(clone)) return true
  
  for (let i=0; i < clone.length; i++) {
    const next = seq[seq.length - 1] + 1
    if (clone[i] === next) {
      seq.push(clone[i])
      clone.splice(i, 1)
      i--
      if (isPossible(clone)) return true
    }
  }
  return false
};