Fibonacci algorithms

fibonacciAlgorithms.js

function fiboLoop(num) {
  let a = 1,
    b = 0,
    temp;

  while (num >= 1) {
    temp = a;
    a += b;
    b = temp;
    num--;
  }

  return b;
}

function fiboRec(num) {
  if (num <= 2) return 1;

  return fiboRec(num - 1) + fiboRec(num - 2);
}

function fiboMemo(num, memo) {
  memo = memo || {};

  if (memo[num]) return memo[num];
  if (num <= 2) return 1;

  return memo[num] = fiboMemo(num - 1, memo) + fiboMemo(num - 2, memo);
}

function fiboFormula(n) {
  const Phi = (1 + Math.sqrt(5)) / 2;
  const phi = (1 - Math.sqrt(5)) / 2;
  const result = (Math.pow(Phi, n) - Math.pow(phi, n)) / Math.sqrt(5);
  return Math.round(result);
}  

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