如何检查一个数字是否是斐波纳契数？

Question

我试图创建一个函数来确定Scala中的数字是否是斐波纳契数。有人可以看看我的代码，让我知道我错过了什么？感谢

def isFibNumber(n: Int): Boolean = {

  var fib1 = 0;
  var  fib2 = 1;
do {
    var saveFib1 = fib1;
    fib1 = fib2;
    fib2 = saveFib1 + fib2;
    }
while (fib2 < n);

if (fib2 == n)
    return true;
else
    return false;
}

Answer 1

def isFibonacciNumber(n: Int): Boolean = {
  var fib1 = -1;
  var  fib2 = 1;
  var res = 0;

do {
    res = fib1+fib2;
    fib1 = fib2;
    fib2 = res;
} while (res < n);

if (res == n)
    return true;
else
    return false;
}

这应该有效。您的算法中有错误。

Answer 2

那会有所帮助。无需循环

http://www.geeksforgeeks.org/check-number-fibonacci-number/

object Fib {


  def isPerfectSq(n: Int): Boolean = {
    val res = math.round(math.sqrt(n))
    res * res == n.toLong
  }

  def isFibonacci(n: Int) = {
    isPerfectSq(5 * n * n - 4) || isPerfectSq(5 * n * n + 4)
  }


}