1114.js

// 1114.js

const arr = [0, 1, 12, 24, 36]
const start = 2

const f1 = (arr, start) => {
  const head = arr.slice(0, 2)
  const tail = arr.slice(start + 2)
  return [...head, 16, 25, ...tail]
}

const f2 = (arr, start) => {
  const head = arr.slice(0, 2)
  const tail = arr.slice(start)
  return [...head, 4, 9, ...tail]
}

const f3 = (arr, start) => {
  const head = arr.slice(0, 2)
  const tail = arr.slice(start + 2)
  return [...head, ...tail]
}

const f4 = (arr, start) => {
  const head = arr.slice(0, 2)
  return head
}