Transposing and Untransposing a String in java

int c = a[r - 1].length;

@Test
    public void transpose() {

        final int[][] original = new int[][] { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 } };
        for (int i = 0; i < original.length; i++) {
            for (int j = 0; j < original[i].length; j++) {
                System.out.print(original[i][j] + " ");
            }
            System.out.print("\n");
        }
        System.out.print("\n\n matrix transpose:\n");
        // transpose
        if (original.length > 0) {
            for (int i = 0; i < original[0].length; i++) {
                for (int j = 0; j < original.length; j++) {
                    System.out.print(original[j][i] + " ");
                }
                System.out.print("\n");
            }
        }
    }

1 2 3 4 
5 6 7 8 
9 10 11 12 


 matrix transpose:
1 5 9 
2 6 10 
3 7 11 
4 8 12 

    NOT EXISTS (SELECT *
        FROM
           tabl2 T2
        WHERE
           T1.ID = trim(x.column_value.extract('e/text()')))
    AND t1.str_work IS NOT NULL);

a = str.split("\n")
l = a.max_by(&:size).size
puts a.map { |b| b.ljust(l).chars }
      .transpose
      .map { |c| c.join.rstrip }.join("\n")
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a = str.split("\n").map(&:chars)
a.max_by(&:size).size.times.map { a.map { |e| e.shift || ' ' }.join.rstrip }

a = str.split("\n").map(&:chars)
a_empty = Array(a.size, [])
[].tap { |b| b << a.map { |e| e.shift || ' ' }.join.rstrip while a != a_empty }

a = str.split("\n").map(&:chars)
(0..Float::INFINITY).lazy.map do |i|
  a.each { |e| e.shift } if i > 0 
  a.map  { |e| e.first || ' ' }.join.rstrip
end.take_while { c = a.any? { |e| !e.empty? }  }.to_a

def recurse(a, b=[])
  return b[0..-2] if a.last.empty?
  b << a.map { |e| e.shift || ' ' }.join.rstrip
  recurse(a, b)
end

a = str.split("\n").map(&:chars)
recurse(a)

static String transpose( String s ){
    char[] c = s.toCharArray();
    int n = (int)Math.sqrt(s.length());
    for( int i = 0; i < n; ++i ){
        for( int j = i+1; j < n; ++j ){
            char h = c[i*n+j];
            c[i*n+j] = c[j*n+i];
            c[j*n+i] = h;
        }
    }
    return new String( c );
}