mathball/lib/palindrome/index.js

A JavaScript library for Competitive Programming

'use strict';

/* Palindromic Number
 * Function: isPalindrome()
 * Function: rangePal() --> to return all palindromic numbers from 0 to end
 */

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

exports.check = function (num) {
	validate(num, 'isPalindrome');
	return num == num.toString().split('').reverse().join('');
};

exports.range = function (start, end) {
	validate(start, 'rangePal');
	validate(end, 'rangePal');

	if (start > end) {
		throw new TypeError('Starting number must be smaller than the ending number!!\n');
	}
	var palinList = [],
	    lim = 0;

	lim = end < 10 ? end : start;

	for (var i = start; i < lim; i++) {
		palinList.push(i);
	}

	for (var _i = lim; _i < end; _i++) {
		if (_i.toString() === _i.toString().split('').reverse().join('')) {
			palinList.push(_i);
		}
	}

	return palinList;
};