Project Euler #4: Largest palindrome product Discussions |

11 months ago+ 0 comments

using System; using System.Collections.Generic; using System.IO; using System.Linq; class Solution { static void Main(String[] args) { int T = Convert.ToInt32(Console.ReadLine()); for (int a0 = 0; a0 < T; a0++) { int n = Convert.ToInt32(Console.ReadLine()); int largestPalindrome = FindLargestPalindrome(n); Console.WriteLine(largestPalindrome); } }

static bool IsPalindrome(int num) { string numStr = num.ToString(); int len = numStr.Length; int left =0; int right =len-1;

for(int i=0 ; i<=len/2 ; i++)
{
    if(numStr[left]==numStr[right])
    {
        left++;
        right--;
    }
    else
    {return false;}
}

// for (int i = 0; i < len / 2; i++) {
//     if (numStr[i] != numStr[len - 1 - i]) {
//         return false;
//     }
// }

/*
while(left<right)
{
    if(numStr[left]!=numStr[right])
    {
        return false;
        break;
    }
    left++;
    right--;
}
*/
return true;

}

static int FindLargestPalindrome(int n) { for (int i = n - 1; i >= 101101; i--) { if (IsPalindrome(i)) { for (int j = 100; j <= 999; j++) { if (i % j == 0 && i / j >= 100 && i / j <= 999) { return i; } } } } return -1; // If no palindrome is found } }

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