Envío 6248

Código

import java.util.*;

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

        for(int i=0; i<n; i++){
            String claseE = scanner.next();
            String claseT = scanner.next();
            int claseEmpieza = Integer.parseInt(claseE.replace(":", ""));
            int claseTermine = Integer.parseInt(claseT.replace(":", ""));

            clases[i][0]=claseEmpieza;
            clases[i][1]=claseTermine;
        }

        Sort2DArrayBasedOnColumnNumber(clases, 2);
        ArrayList<Integer> horarios = new ArrayList<>();

        for(int i=0; i<n; i++){
        if(i==0){
            horarios.add(clases[i][1]);
            continue;
        }

        int min = Integer.MAX_VALUE;
        int minIndex = -1;
        for(int j=0; j<horarios.size(); j++){
            if(horarios.get(j)<min){
                min = horarios.get(j);
                minIndex = j;
            }
        }

        if(min<=clases[i][0]) {
            horarios.set(minIndex, clases[i][1]);
        } else {
            horarios.add(clases[i][1]);
        }
    }

        System.out.println(horarios.size());
}

    public static void Sort2DArrayBasedOnColumnNumber (int[][] array, final int columnNumber){
        Arrays.sort(array, new Comparator<int[]>() {
            @Override
            public int compare(int[] first, int[] second) {
                if(first[columnNumber-1] > second[columnNumber-1]) return 1;
                else return -1;
            }
        });
    }
}