public static int[] swappy(int a, int b, int c, int d) {
		// [a][b][c][d] <=
		// compare c, d
		if(c==d) {
			c = c + d;
			d = 0;

			// [a][b][c+d][0] now compare a, b
			if(a==b) {
				a = a + b;
				b = c;
				c = 0;

				// [a+b][c+d][0][0]			DONE
			} else if(a==0) {
				a = b;
				b = c;
				c = 0;
				// [b][c+d][0][0]			DONE
			}

		} else if(c==0) {
			c = d;
			d = 0;

			// [a][b][d][0] now compare a, b
			if(a==b) {
				a = a + b;
				b = c;
				c = 0;

				// [a+b][d][0][0]		DONE
			} else if(a==0) {
				a = b;
				b = c;
				c = 0;

				// [b][d][0][0]			DONE
			}
		} else {
			// [a][b][c][d] now compare b and c
			if(b==c) {
				b = b+c;
				c = d;
				d = 0;

				// [a][b+c][d][0]		DONE
			} else if(b==0) {
				// [a][c][d][0]			DONE
				b = c;
				c = d;
				d = 0;
			}
		}
		
		return new int[] {a, b, c, d};
	}