java - Filling a jagged 2d array first by columns

Question

I want to write a function that takes an 2d array and fills it with 1...n but counting the columns first instead of the rows:

input = {{0, 0, 0, 0}, {0}, {0}, {0, 0}};

the output should be: {{1, 5, 7, 8}, {2}, {3}, {4, 6}};

if i were to loop through rows and then colums i get:

private static void fill1(int[][] input) {
    int count = 1;
    for (int i = 0; i < input.length; i++) {
        for (int j = 0; j < input[i].length; j++) {
            input[i][j] = count;
            count++;
        }
    }
}

How do I loop through colums first?

Answer 1

You can do this by first transposing your input, executing your fill1 code and then transposing the output again.
See this question for how to transpose a 2 dimensional array in Java: java multi-dimensional array transposing