mathball/lib/fibonacci/index.js

A JavaScript library for Competitive Programming

'use strict';

/* Fibonacci Number
 * Function: fibonacci()
 */

var validate = require('../validation/positive-integer');

function fib(num) {
	if (num <= 2) {
		return 1;
	}
	var n1 = 1,
	    n2 = 1,
	    total = void 0;
	for (var i = 3; i <= num; i++) {
		total = n1 + n2;
		n1 = n2;
		n2 = total;
	}
	return total;
}

exports.find = function (num) {
	validate(num, 'fibonacci');
	return fib(num);
};

/* Range Fibonacci Number
 * Function: rangeFibonacci()
 */

var rangeFib = function rangeFib(num) {
	var n1 = 0,
	    n2 = 1,
	    nextT = null,
	    rangeArr = [];

	do {
		rangeArr.push(n1);
		nextT = n1 + n2;
		n1 = n2;
		n2 = nextT;
	} while (n1 <= num);
	return rangeArr;
};

exports.range = function (num) {
	validate(num, 'rangeFibonacci');
	return rangeFib(num);
};