square puzzle solution

Question

Question: given an integer number n, print the numbers from 1 up to n² like this:

n = 4

result is:

01 02 03 04
12 13 14 05
11 16 1         


        

Answer 1

Though your example is in python and this is in Java, I think you should be able to follow the logic:

public class SquareTest {

public static void main(String[] args) {
    SquareTest squareTest = new SquareTest(4);
    System.out.println(squareTest);
}

private int squareSize;
private int[][] numberSquare;
private int currentX;
private int currentY;
private Direction currentDirection;

private enum Direction {
    LEFT_TO_RIGHT, RIGHT_TO_LEFT, TOP_TO_BOTTOM, BOTTOM_TO_TOP;
};

public SquareTest(int squareSize) {
    this.squareSize = squareSize;
    numberSquare = new int[squareSize][squareSize];
    currentY = 0;
    currentX = 0;
    currentDirection = Direction.LEFT_TO_RIGHT;
    constructSquare();
}

private void constructSquare() {
    for (int i = 0; i < squareSize * squareSize; i = i + 1) {
        numberSquare[currentY][currentX] = i + 1;
        if (Direction.LEFT_TO_RIGHT.equals(currentDirection)) {
            travelLeftToRight();
        } else if (Direction.RIGHT_TO_LEFT.equals(currentDirection)) {
            travelRightToLeft();
        } else if (Direction.TOP_TO_BOTTOM.equals(currentDirection)) {
            travelTopToBottom();
        } else {
            travelBottomToTop();
        }
    }
}

private void travelLeftToRight() {
    if (currentX + 1 == squareSize || numberSquare[currentY][currentX + 1] != 0) {
        currentY = currentY + 1;
        currentDirection = Direction.TOP_TO_BOTTOM;
    } else {
        currentX = currentX + 1;
    }
}

private void travelRightToLeft() {
    if (currentX - 1 < 0 || numberSquare[currentY][currentX - 1] != 0) {
        currentY = currentY - 1;
        currentDirection = Direction.BOTTOM_TO_TOP;
    } else {
        currentX = currentX - 1;
    }
}

private void travelTopToBottom() {
    if (currentY + 1 == squareSize || numberSquare[currentY + 1][currentX] != 0) {
        currentX = currentX - 1;
        currentDirection = Direction.RIGHT_TO_LEFT;
    } else {
        currentY = currentY + 1;
    }
}

private void travelBottomToTop() {
    if (currentY - 1 < 0 || numberSquare[currentY - 1][currentX] != 0) {
        currentX = currentX + 1;
        currentDirection = Direction.LEFT_TO_RIGHT;
    } else {
        currentY = currentY - 1;
    }
}

@Override
public String toString() {
    StringBuilder builder = new StringBuilder();
    for (int i = 0; i < squareSize; i = i + 1) {
        for (int j = 0; j < squareSize; j = j + 1) {
            builder.append(numberSquare[i][j]);
            builder.append(" ");
        }
        builder.append("\n");
    }

    return builder.toString();
}
}