Take only equal elements in a matrix

Question

I have a matrix for example:

1 4 7
1 3 4 6 7
1 2 3 4 5 6

I have to see the repeating numbers in ALL lines, in the example, the numbers should be the result: 1 and 4. For it is they who repeat in all lines.

Vector<Integer> validos = new Vector<Integer>();
int cont = 0;
for (int linha = 0; linha < resultado.length; linha++)
{

    for (int coluna = 0; coluna < resultado.length - 1; coluna++)
    {
        for (int linha2 = (linha + 1); linha2 < resultado.length; linha2++)
        {
            for (int coluna2 = 0; coluna2 < resultado.length - 1; coluna2++)
            {
                if(resultado[linha][coluna] == resultado[linha2][coluna2])
                {
                    cont ++;
                }
            }
        }
    }
}

Where the matrix is the variable resultado, which is a int[][], tried to implement a cont that if there were the number on all rows it would then be worth the number of rows in the matrix, example, 3.

Only the code isn’t working.

The goal is to take these repeated numbers and put in the Vector validos

Answer 1

I don’t know which language you wrote. Anyway I wrote in C#, you will know how to make the adaptations with the class names List, Vector, etc..

At the end of the code, in the variable int[] validos will only have 1, 2, 3. How do you want, but I had to add 3 on the first level of the matrix because it didn’t exist.

        int[][] vetor = new int[][] {
            new int[] { 1, 3, 4, 7 },
            new int[] { 1, 3, 4, 6, 7 },
            new int[] { 1, 2, 3, 4, 5, 6 }
        };

        List<int> validosList = new List<int>();

        for (int i = 0; i < vetor.Length; i++)
        {
            for (int j = 0; j < vetor[i].Length; j++)
            {
                int numero = vetor[i][j];

                if (validosList.Contains(numero))
                {
                    continue; //Número já validado. Pula essa verificação.
                }

                int contagem = 0;

                for (int k = 0; k < vetor.Length; k++)
                {
                    for (int l = 0; l < vetor[k].Length; l++)
                    {
                        int numeroEmVerificacao = vetor[k][l];

                        if (numero == numeroEmVerificacao)
                        {
                            contagem++;
                            break; //Vai pra próxima linha do array
                        }
                    }                        
                }

                if (contagem == vetor.Length)
                {
                    validosList.Add(numero);
                }

            }
        }

        int[] validos = validosList.ToArray();