1.4 KiB
1.4 KiB
title |
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Largest palindrome product |
Problem 4: Largest palindrome product
Method:
- A palindromic number is the one that when reversed reads the same.
- The largest number obtained from product of two 3 digit number is
999 * 999
, so we can make a loop that starts by producting the largest number and check if that number is palindromic or not.
Solution:
function largestPalindromeProduct(n) {
//To get the maximum n digit number, + operator type castes String to Number type
let max = +[...Array(n)].reduce((a, c) => a+=9, "");
//Next we get minimum n digit number from the max
let min = (max+1)/10;
//To store the result
let res = [];
//Starting the loop from max to min
for (let i = max; i >= min; i--){
//Another loop
for (let j = max; j >= min; j--){
//Getting the product
let num = i*j;
//Reversing the number
let numReverse = [...String(num)].reverse().join('');
//Checking for palindromic number
if (num == numReverse) {
//Pushing the number into array and breaking the loop for efficiency
res.push(num);
break;
}
}
}
// Returning the maximum of the result array
return Math.max(...res);
}