vz0

/*

My output:

25037
13204
13796

*/

public class MatrixTest {

    public int width;
    public int height;
    public int m[];

    public MatrixTest(int w, int h) {
        this.width = w;
        this.height = h;
        this.m = new int[w * h];
    }

    public int get(int x, int y) {
        return this.m[y * width + x];
    }

    public void set(int x, int y, int value) {
        this.m[y * width + x] = value;
    }

    public static void main (String[] args) {
        int w = 1000, h = 2000, passes = 400;

        int matrix[][] = new int[h][];

        for (int i = 0; i < h; ++i) {
            matrix[i] = new int[w];
        }

        long start;

        start = System.currentTimeMillis();

        // X and Y are inverted.

        for (int z = 0; z < passes; z++) {
            for (int x = 0; x < w; x++) {
                for (int y = 0; y < h; y++) {
                    matrix[y][x] = matrix[y][x] + 1;
                }
            }
        }

        System.out.println(System.currentTimeMillis() - start);

        //

        MatrixTest mt = new MatrixTest(w, h);

        start = System.currentTimeMillis();

        for (int z = 0; z < passes; z++) {
            for (int x = 0; x < w; x++) {
                for (int y = 0; y < h; y++) {
                    mt.set(x, y, mt.get(x, y) + 1);
                }
            }
        }

        System.out.println(System.currentTimeMillis() - start);

        //

        MatrixTest mt2 = new MatrixTest(w, h);

        start = System.currentTimeMillis();

        for (int z = 0; z < passes; z++) {
            for (int x = 0; x < w; x++) {
                for (int y = 0; y < h; y++) {
                    mt2.m[y * w + x] = mt2.m[y * w + x] + 1;
                }
            }
        }

        System.out.println(System.currentTimeMillis() - start);
    }
}