public class SwapStore implements SwapStoreInterface {
    private String[][][] core;

    @Override
    public void set(String[][] words) {
        core = new String[words.length][1][];
        for (int i = 0; i < words.length; i++) {
            core[i][0] = words[i];
        }
    }
    @Override
    public int[] lineIndices(int line) {
        int[] result = new int[core[line].length * core[line][0].length];
        for (int i = 0; i < core[line].length; i++) {
            for (int j = 0; j < core[line][i].length; j++) {
                result[(i+1)*(j+1)-1] = j;
            }
        }
        return result;
    }
    @Override
    public void setShifts(int line, int[][] shiftedIndices) {
        String[][] tmp = new String[shiftedIndices.length][];
        for (int i = 0; i < shiftedIndices.length; i++) {
            String[] shift = new String[shiftedIndices[i].length];
            for (int j = 0; j < shift.length; j++) {
                shift[j] = core[line][0][shiftedIndices[i][j]];
            }
            tmp[i] = shift;
        }
        core[line] = tmp;
    }
    @Override
    public void swap(int i, int j, int k) {
        String[] tmp = core[i][j];
        core[i][j] = core[i][k];
        core[i][k] = tmp;
    }
    @Override
    public int compare(int i, int j, int k) {
        int result = 0;
        int w = 0; // w for word
        while (core[i].length > 0 && result == 0 
                && w < Math.min(core[i][j].length, core[i][k].length)) {
            result = core[i][j][w].compareTo(core[i][k][w]);
            w++;
        }
        return result;
    }
    @Override
    public int length() {
        return core.length;
    }
    @Override
    public int lineLength(int i) {
        return core[i].length;
    }
    @Override
    public String get() {
        String result = "";
        for (String [][] line : core) {
            for (String[] shift : line) {
                for (String word : shift) {
                    result += word + ' ';
                }
                result += ", ";
            }
            result += '\n';
        }
        return result;
    }
}