function solve ([x1, y1, x2, y2]) {
  function printResult (x1, y1, x2, y2) {
    let isValid = Number.isInteger(Math.hypot(x1 - x2, y1 - y2))
      ? 'valid'
      : 'invalid'
    console.log(`{${x1}, ${y1}} to {${x2}, ${y2}} is ${isValid}`)
  }

  printResult(x1, y1, 0, 0)
  printResult(x2, y2, 0, 0)
  printResult(x1, y1, x2, y2)
}