03. Histogram

import java.util.Scanner;

public class Histogram {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = Integer.parseInt(scanner.nextLine());

        int p1 = 0, p2 = 0, p3 = 0, p4 = 0, p5 = 0;

        for (int i = 1; i <= n; i++) {
            int number = Integer.parseInt(scanner.nextLine());
            if (number < 200) {
                p1 += 1;
            } else if (number < 400) {
                p2 += 1;
            } else if (number < 600) {
                p3 += 1;
            } else if (number < 800) {
                p4 += 1;
            } else {
                p5 += 1;
            }
        }

        System.out.printf("%.2f%%\n", (double)p1 / n * 100);
        System.out.printf("%.2f%%\n", (double)p2 / n * 100);
        System.out.printf("%.2f%%\n", (double)p3 / n * 100);
        System.out.printf("%.2f%%\n", (double)p4 / n * 100);
        System.out.printf("%.2f%%\n", (double)p5 / n * 100);
    }
}

ИЛИ:

import java.util.Scanner;

public class Histogram {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = Integer.parseInt(scanner.nextLine());

        int p1 = 0, p2 = 0, p3 = 0, p4 = 0, p5 = 0;

        for (int i = 1; i <= n; i++) {
            int number = Integer.parseInt(scanner.nextLine());
            if (number < 200) {
                p1 += 1;
            } else if (number < 400) {
                p2 += 1;
            } else if (number < 600) {
                p3 += 1;
            } else if (number < 800) {
                p4 += 1;
            } else {
                p5 += 1;
            }
        }

        for (int p : new int[]{p1, p2, p3, p4, p5}) {
            System.out.printf("%.2f%%\n", (double) p / n * 100);
        }
    }
}

ИЛИ:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = Integer.parseInt(scanner.nextLine());

        int[] histogram = new int[]{0, 0, 0, 0, 0};

        for (int i = 1; i <= n; i++) {
            int number = Integer.parseInt(scanner.nextLine());
            histogram[(number < 200 ? 0 : number < 400 ? 1 : number < 600 ? 2 : number < 800 ? 3 : 4)]++;
        }

        for (int p : histogram) {
            System.out.printf("%.2f%%\n", (double) p / n * 100);
        }
    }
}