How to inform the largest consecutive sequence?

Question

Guys I’m hooked on this algorithm where I create an integer vector with n positions and need to show the longest consecutive sequence.

I will leave the statement to try to be more specific.

"Elaborate an algorithm where the user type 50 integer numbers of a vector and at the end the program tells the size of the largest consecutive increasing sequence."

ex:

6,7,9. Capital = 2.

5,6,7,8,11. Most important = 4

What I’ve done so far:

public class Questao02 {

        public static void main(String[] args){
            String aux;
            int a[] = new int[5];
            int cont=0;

            for(int i=0;i<5;i++){
                aux = JOptionPane.showInputDialog("Números");
                a[i] = Integer.parseInt(aux);

                if(a[i] < a[i+1] ){
                    cont++;

                }

                else{
                    cont=0;

                }

            }

            System.out.println(cont);
        }
}

Answer 1

It is important to separate the introduction of values from the logic of accounting. In this case it even simplifies because the accounting cannot be done for all values because it considers the front value, so it has to finish one before the end.

You also need another variable to store the maximum string found so far, otherwise when the cont back to 0 loses the previous sequence that could even be larger.

public static void main(String[] args) {
    int a[] = new int[5];
    int cont = 0;
    int maior = 0; //nova variável para a maior sequencia achada

    //só a leitura
    for(int i=0;i<5;i++){
        //sem aux para simplificar
        a[i] = Integer.parseInt(JOptionPane.showInputDialog("Números"));
    }

    //só a contabilização
    for(int i=0;i<4;i++){ //até ao 4, um antes do fim
        if(a[i] == a[i+1]-1){ //teste de valor 1 abaixo, em vez de apenas inferior
            cont++;

            //verifica e atualiza com a maior sequência
            if (cont > maior){  achada até ao momento
                maior = cont;
            }
        }
        else{
            cont=0;
        }
    }

    //quando testa se o número é sequencia com o da frente o maior vai ficar com 1 mas
    //a sequência já representa dois números, logo é necessário no fim somar 1
    maior++;
    System.out.println(maior);
}

Considerations:

• Just like Articuno this is not a good idea to mix GUI and console mode, so consider using Scanner and nextInt() for reading, for consistency.
• The way the parseInt can launch an exception if the user does not enter a number. Please consider using exception handling with try catch if you want to prevent the program from exploding in this case.