906-Super-Palindromes.js

/**
 * @param {string} left
 * @param {string} right
 * @return {number}
 */
const superpalindromesInRange = (left, right) => {
    const superpalindromes = [
        1,
        4,
        9,
        121,
        484,
        10201,
        12321,
        14641,
        40804,
        44944,
        1002001,
        1234321,
        4008004,
        100020001,
        102030201,
        104060401,
        121242121,
        123454321,
        125686521,
        400080004,
        404090404,
        10000200001,
        10221412201,
        12102420121,
        12345654321,
        40000800004,
        1000002000001,
        1002003002001,
        1004006004001,
        1020304030201,
        1022325232201,
        1024348434201,
        1210024200121,
        1212225222121,
        1214428244121,
        1232346432321,
        1234567654321,
        4000008000004,
        4004009004004,
        100000020000001,
        100220141022001,
        102012040210201,
        102234363432201,
        121000242000121,
        121242363242121,
        123212464212321,
        123456787654321,
        400000080000004,
        10000000200000001,
        10002000300020001,
        10004000600040001,
        10020210401202001,
        10022212521222001,
        10024214841242001,
        10201020402010201,
        10203040504030201,
        10205060806050201,
        10221432623412201,
        10223454745432201,
        12100002420000121,
        12102202520220121,
        12104402820440121,
        12122232623222121,
        12124434743442121,
        12321024642012321,
        12323244744232321,
        12343456865434321,
        12345678987654321,
        40000000800000004,
        40004000900040004
    ];

    let count = 0;
    for (const item of superpalindromes) {
        if (+left <= item && item <= +right) count++;
    }

    return count;
};