#!/usr/bin/env node;
/******************************************************************************
 * This program compares recursion to iteration in computing palindromes.
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

const Utils = require('./Utils');

const TEST_CASES = ["Hannah", "Able was I ere I saw Elba", "A man, a plan, a canal – Panama", "T. Eliot, top bard, notes putrid tang emanating, is sad; I'd assign it a name: gnat dirt upset on drab pot toilet.", "This is not a palindrome!"];

function palindromeRecursive0(s) {
    const S_LEN = Utils.cpLength(s);
    if (S_LEN < 2) {
        return true;
    }
    if (Utils.cpAt(s, 0) !== Utils.cpAt(s, S_LEN - 1)) {
        return false;
    }
    return palindromeRecursive0(Utils.cpSubstr(s, 1, (S_LEN - 1) - 1));
}

function palindromeRecursive(s) {
    let s0 = s.replaceAll(/\W+/g, "");
    s0 = s0.toLowerCase();
    return palindromeRecursive0(s0);
}

function palindromeIterative(s) {
    let s0 = s.replaceAll(/\W+/g, "");
    s0 = s0.toLowerCase();
    const S_LEN = Utils.cpLength(s0);
    for (let x = 0; x <= Math.trunc((S_LEN - 1) / 2); ++x) {
        if (Utils.cpAt(s0, x) !== Utils.cpAt(s0, S_LEN - 1 - x)) {
            return false;
        }
    }
    return true;
}

const main = async () => {
    for (let s of TEST_CASES) {
        console.log(["Test Case: ", s].join(''));
        let result = palindromeRecursive(s);
        console.log(["palindromeRecursive: ", (result ? "Yes" : "No")].join(''));
        result = palindromeIterative(s);
        console.log(["palindromeIterative: ", (result ? "Yes" : "No")].join(''));
    }
}
main().catch( e => { console.error(e) } );