palindromes

palindromes.js

'use strict';

var assert = require('assert');

function reverseString(str) {
    return str.split('').reverse().join('');
}

function getRotations(str) {
    str = str.trim();

    var rotations = [];

    rotations.push(str);

    for (var pos = 1; pos < str.length; pos++) {
        var left = str.substr(0, pos);
        var right = str.substr(pos);

        var rotation = reverseString(left) + reverseString(right);

        rotations.push(rotation);
    }

    return rotations;
}

function getPalindromes(str) {
    return getRotations(str).filter(validPalindrome);
}

function validPalindrome(str) {
    var valid = true;

    if (!str) {
        valid = false;
    }

    var splitted = str.split('');

    while (splitted.length > 0 && valid === true) {
        var left = splitted.shift();
        var right = splitted.pop();

        if (left && right && left !== right) {
            valid = false;
            break;
        } else if(splitted.length === 2 && splitted[0] === splitted[1]) {
            break;
        }
    }

    return valid;
}

function testPalindromes() {
    var palin;

    palin = getPalindromes('asd');
    assert (palin.length === 0);

    palin = getPalindromes('alabala');
    assert (palin.length === 1);
    assert (palin[0] === 'alabala');

    palin = getPalindromes('akawwaka');
    assert (palin.length === 2);
    assert (palin[0] === 'akawwaka');
    assert (palin[1] === 'wakaakaw');

    palin = getPalindromes('b');
    assert (palin.length === 1);
    assert (palin[0] === 'b');

    palin = getPalindromes('abba');
    assert (palin.length === 2);
    assert (palin[0] === 'abba');
    assert (palin[1] === 'baab');

    palin = getPalindromes('kamak');
    assert (palin.length === 1);
    assert (palin[0] === 'kamak');

    palin = getPalindromes('bird');
    assert (palin.length === 0);

    palin = getPalindromes('');
    assert (palin.length === 0);

    console.log('tests passed!');
}

//testPalindromes();

var stdinData = '';

process.stdin.on('readable', function() {
    var chunk = process.stdin.read();

    if (chunk !== null) {
        stdinData = stdinData + chunk;
    } else {
        var palindromes = getPalindromes(stdinData);

        if (palindromes.length) {
            palindromes.forEach(function(palin) {
                console.log(palin);
            });
        } else {
            console.log('NONE');
        }
    }
});