import java.util.Scanner; public class prog { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int n = 2; int[][] land = new int[n][n]; int currentYLeft = 0; int currentYRight = n - 1; int currentX = 0; while (true) { if(currentYRight < currentYLeft) { currentX++; currentYLeft = 0; currentYRight = n; continue; } int currentY = (currentYRight + currentYLeft) / 2; System.out.println(currentX + " " + currentY); String line = scanner.nextLine(); int alt; try { alt = Integer.parseInt(line); land[currentX][currentY] = alt; if(alt == 0) { break; } else if(alt < 0) { currentYLeft = currentY + 1; } else { currentYRight = currentY - 1; } } catch (NumberFormatException e) { // TODO Auto-generated catch block e.printStackTrace(); } } scanner.close(); } }