Topic

Multidimensional array

Problem

Cinema

https://hyperskill.org/learn/step/1930

The cinema has n rows, each row consists of m seats (n and m do not exceed 20). A two-dimensional matrix stores the information on the sold tickets: the number 1 means that the ticket for this place is already sold, and the number 0 means that the place is available. You want to buy k tickets to neighboring seats in the same row. Find whether it can be done.

Input data format

On the input, the program gets the number of n rows and m seats. Then, there are n lines, each containing m numbers (0 or 1) separated by spaces. The last line contains the number k.

Output data format

The program should output the number of the row with k consecutive available seats. If there are several rows with k available seats, output the first row with these seats. If there is no such a row, output the number 0.

Sample Input 1:

3 4
0 1 0 1
1 1 0 1
1 0 0 1
2

Sample Output 1:

3

Sample Input 2:

3 3
0 1 0
1 0 0
1 1 1
3

Sample Output 2:

0

Sample Input 3:

2 4
1 1 0 0
0 0 1 1
4

Sample Output 3:

0

Hint & Explain

If you're using a counter, remember to reset it when going from row to row.

Solution

My solution

import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        // put your code here
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();  // rows
        int m = scanner.nextInt();  // seats

        int[][] matrixOfSeats = new int[n][m]; // matrix

        for (int i = 0; i < matrixOfSeats.length; i++) {
            for (int j = 0; j < matrixOfSeats[i].length; j++) {
                matrixOfSeats[i][j] = scanner.nextInt();
            }
        }

        int k = scanner.nextInt(); // target
        int counter;
        int temp = 0;
        int targetOfRow = 0;
        boolean stop = false;

        for (int i = 0; i < matrixOfSeats.length; i++) {
            counter = 0;
            for (int j = 0; j < matrixOfSeats[i].length; j++) {
                if (matrixOfSeats[i][j] == 0) {
                    counter++;
                    temp = counter;

                    if (temp >= k) {
                        targetOfRow = i + 1;
                        stop = true;
                        break;
                    }

                } else {
                    counter = 0;
                }
            }
            if (stop) {
                break;
            }
        }

        System.out.println(targetOfRow);

    }
}

Other solution 1 (Pretty code!!!)

import java.util.Scanner;

class Main {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int n = scanner.nextInt();
        int m = scanner.nextInt();

        int[][] table = new int[n][m];

        int number;

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                number = scanner.nextInt();
                table[i][j] = number;
            }
        }

        int k = scanner.nextInt();

        int counter;

        int i = 0;

        boolean available = false;

        LOOP:
        for (; i < n; i++) {
            counter = 0;
            for (int j = 0; j < m; j++) {
                if (table[i][j] == 0) {
                    counter++;
                } else {
                    counter = 0;
                }
                if (counter == k) {
                    available = true;
                    break LOOP;
                }
            }
        }

        if (available) {
            System.out.println(i + 1);
        } else {
            System.out.println(0);
        }

    }

}

Other solution 2

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int row = sc.nextInt();
        int col = sc.nextInt();
        int[][] seats = new int[row][col];

        for (int i = 0; i < row; i++) {
            for (int j = 0; j < col; j++) {
                seats[i][j] = sc.nextInt();
            }
        }

        int k = sc.nextInt();
        int count = 0;
        int maxCount = 0;

        for (int i = 0; i < row; i++) {
            count = 0;
            for (int j = 0; j < col; j++) {
                if (seats[i][j] == 0) {
                    count++;
                } else {
                    count = 0;
                }

                if (count > maxCount) {
                    maxCount = count;
                }
            }
            if (maxCount >= k) {
                System.out.println(i + 1);
                return;
            }
        }

        System.out.println(0);
    }
}

Other solution 3

import java.util.Scanner;

class Main {

    public static String[] seats;
    public static int requiredTickets = 0;

    public static void main(String[] args) {
        // put your code here
        readInput();
        for (int i = 0; i < seats.length; i++) {
            if (seats[i].contains("0".repeat(requiredTickets))) {
                System.out.println(i + 1);
                return;
            }
        }
        System.out.println(0);
    }

    public static void readInput() {
        Scanner scanner = new Scanner(System.in);
        String buf = scanner.nextLine();
        String[] bufSplitted = buf.split(" ");
        int rows = Integer.parseInt(bufSplitted[0]);
        seats = new String[rows];
        for (int i = 0; i < rows; i++) {
            seats[i] = scanner.nextLine().replace(" ", "");
        }
        requiredTickets = scanner.nextInt();
    }
}