#!/usr/bin/python
# jumpsaround - jumper game
# (c) 2011 Alexander Kulbartsch

SIZEX = 6
SIZEY = 5

jump = ((-1,-2), (1,-2), (-2,-1), (2,-1), (-2,1), (2,1), (-1,2), (1,2))

# init board
board = []
for i in range(SIZEX):
    col = []
    for i in range(SIZEY):
        col.append(0)
    board.append(col)

solutions = 0
roundtrips = 0

def jumpto(x, y, iter):
    global solutions
    global roundtrips
    global board

    board[x][y] = iter

    # finished?
    if iter >= SIZEX * SIZEY:
        # check for roundtrips
        round = 0
        for np in jump:
            nx = x + np[0]
            ny = y + np[1]
           	# check if position is on the board
            if nx < 0 or nx > (SIZEX-1) or ny < 0 or ny > (SIZEY-1):
                continue
            # detect roundtrip
            if board[nx][ny] == 1:
                round = True
                roundtrips += 1
                break
        solutions += 1
        printboard(round)
        board[x][y] = 0
        return

    # try next jump
    for np in jump:
        nx = x + np[0]
        ny = y + np[1]
        # check if position is on the board
        if nx < 0 or nx > (SIZEX-1) or ny < 0 or ny > (SIZEY-1):
            continue
        # check if new field position is still empty
        if board[nx][ny] != 0:
            continue
        jumpto(nx, ny, iter + 1)
    board[x][y] = 0


def printboard(round):
    # The syntax in the following line is not accepted by PyPy
    # print(f"===== Solution #{solutions} - Roundtripps:{roundtrips} ======")
    print('===== Solution #{} - Roundtripps:{} ======'.format(solutions, roundtrips))
    if round:
        print("*** Roundtrip ***")
    for i in range(SIZEY):
        for j in range(SIZEX):
            print(f"{board[j][i]:2d}", end=":")
            # print("{}".format(board[j][i]), end=":")
        print("")
    print()

print("Hello, Jumper!")

jumpto(0, 0, 1)

print("I am done.")

# EOF