AtCoder Beginner Contest 097

ColorfulTransceivers.java

import java.util.Scanner;

class ColorfulTransceivers {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();

        if (Math.abs(a - c) <= d){
            System.out.print("Yes");
        } else if (Math.abs(a-b) <=d && Math.abs(b-c) <= d) {
            System.out.print("Yes");
        } else{
            System.out.print("No");
        }
    }
}

Exponential.java

import java.util.Scanner;

class Exponential {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int X = scanner.nextInt();
        int max = 1;
        for (int x = X / 2; x > 1; x--) {
            for (int y = X / 2; y > 1; y--) {
                double pow = Math.pow((double) x, (double) (y));
                if (pow > max && pow < X) {
                    max = ((int) pow);
                }
            }
        }
        System.out.print(max);
    }
}

KthSubstring.java

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

class KthSubstring {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        int K = scanner.nextInt();

        List<String> strings = new ArrayList<>();

        for (int i = 0; i < s.length(); i++) {
            for (int j = 1; j < 6; j++) {
                if (i + j > s.length()) {
                    break;
                }

                String sub = s.substring(i, i + j);
                if (!strings.contains(sub)){
                    strings.add(sub);
                }
            }
        }

        // sort
        Collections.sort(strings);
        System.out.print(strings.get(K - 1));
    }
}