Incognito wtfCTF 2021: V4l1DaT3

import java.util.Scanner;

public class Main{

     public static void main(String []args){
        System.out.println("Hello World");
        validate flag = new validate();
        System.out.println("Enter flag : ");
        Scanner input = new Scanner("System.in");
        String inputFlag = input.nextLine();
        
        if(flag.valid(inputFlag)==1)
        {
            System.out.println("Correct!");
        }
        else
        {
            System.out.println("Incorrect");
        }
     }
}

class validate{
    int valid(String str) {

        char[] input = str.toCharArray();
        int i, j, flag = 1;
        String str1 = "CmpFny4T@1d";
        if(input.length!=18) return 0;
        char letters[] = str1.toCharArray();
        for (i = 4; i < 18; i++) {
            for (j = 0; j < letters.length; j++) {
                flag = 1;
                if (input[i] == letters[j]) {
                    flag = 0;
                    break;
                }
            }
            if (flag == 1) {
                break;
            }
        }
        if (flag == 1) {
            return 0;
        }
        if (input[0] != 'k') return 0;
        if (input[1] != '3') return 0;
        if (input[2] != '3') return 0;
        if (input[3] != 'p') return 0;

        if (input[4] != input[15]) return 0;
        if (input[5] != input[8]) return 0;
        if (input[6] != input[12]) return 0;

        if ((input[7] - input[4]) != 42) return 0;
        if ((input[7] + 1) != input[9]) return 0;
        if ((input[9] % input[8]) != 46) return 0;
        if ((input[11] - input[8] + input[2]) != 'c') return 0;
        if ((input[14] - input[6]) != (input[17] + 2)) return 0;
        if ((input[9] % input[5]) * 2 != (input[13] + 40)) return 0;
        if ((input[4] % input[13]) != 15) return 0;
        if ((input[14] % input[13]) != (input[12] - 32)) return 0;
        if (((input[7] % input[6]) + 89) != input[10]) return 0;
        if ((input[16] % input[15]) != 17) {
            System.out.println((input[16] % input[15]));
            return 0;
        }
        int x = 0;
        int y = 132;
        for (i = 4; i < 18; i++) {
            x = x ^ input[i];
            y = y + input[i];
        }
        if (x != 72) return 0;
        if (y != 1250) return 0;

        return 1;
    }
}

from itertools import product

def validate(flag):
    input = [ord(i) for i in flag]
    if input[7] - input[4] != 42:
        return False
    if input[7] + 1 != input[9]:
        return False
    if input[9] % input[8] != 46:
        return False
    if chr(input[11] - input[8] + input[2]) != 'c':
        return False
    if (input[14] - input[6]) != (input[17] + 2):
        return False
    if (input[9] % input[5]) * 2 != (input[13] + 40):
        return False
    if (input[4] % input[13]) != 15:
        return False
    if (input[14] % input[13]) != (input[12] - 32):
        return False
    if ((input[7] % input[6]) + 89) != input[10]:
        return False
    if (input[16] % input[15]) != 17:
        return False
    x = 0
    y = 132
    for i in range(4, 18):
        x = x ^ input[i]
        y = y + input[i]
    if x != 72:
        return False
    if y != 1250:
        return False
    return True

str1 = [i for i in "CmpFny4T@1d"]
for prop in product(str1, repeat=6):
    flag = ['' for i in range(18)]
    s = 0
    for i, j in enumerate(prop):
        while i + s in [5-4, 12-4, 15-4, 7-4, 9-4, 11-4, 17-4, 8-4]:
            s += 1
        flag[4+i+s] = j
    try:
        flag[0] = 'k'
        flag[1] = '3'
        flag[2] = '3'
        flag[3] = 'p'
        flag[15] = flag[4]
        flag[12] = flag[6]
        flag[7] = chr(ord(flag[4]) + 42)
        flag[9] = chr(ord(flag[7]) + 1)
        flag[8] = chr(ord(flag[9]) - 46)
        flag[5] = flag[8]
        flag[11] = chr(ord('c') + ord(flag[8]) - ord(flag[2]))
        flag[17] = chr(ord(flag[14]) - ord(flag[6]) - 2)
    except ValueError:
        continue
    if validate(flag):
        print('wtfCTF{{{}}}'.format(''.join(flag)))
        break

wtfCTF{k33pC@1m@ndp14yCTF}