0004.md

let max = -Infinity;
for (let i=100; i<1000; i++) {
    // it's mirror
    for (let j=i; j<1000; j++) {
        let num = i*j;
        if (isPlalindrome(num)) {
            max = Math.max(max, num);
        }
    } 
}

console.log(max);

function isPlalindrome(num) {
    let str = String(num);
    let len = str.length;
    let mid = Math.floor(len/2);
    for (let i=0; i<mid; i++) {
        if (str[i] !== str[len-i-1]) {
            return false;
        }
    }
    return true;
}