ships.py

import random
import string

def pboard():
    for i in board:
        print(''.join(i))

def countf(what):
    cnt = 0
    for i in board:
        cnt += sum(i.count(x) for x in what)
    return cnt 

def get(y, x):
    if y < 0 or y > 9 or x < 0 or x > 9: return '!'
    return board[y][x]

def around(y, x, diagonal, matching):
    coords = [(0, 1), (0, -1), (1, 0), (-1, 0)]
    if diagonal:
        coords += [(1, 1), (1, -1), (-1, 1), (-1, -1)]
    return [(y + yi, x + xi) for yi, xi in coords
            if get(y + yi, x + xi) != '!' and (matching == None or get(y + yi, x + xi) in matching)]

def fill(y, x):
    if get(y, x) == ' ':
        board[y][x] = '.'
        return 0
    elif get(y, x) == '*':
        board[y][x] = '@'
        return sum(fill(yn, xn) for yn, xn in around(y, x, True, None)) + 1
    return 0

def cntdown(y, x):
    cnt, cnt2 = 0, 0
    while get(y + cnt, x) == ' ': cnt += 1
    while get(y - cnt2, x) == ' ': cnt2 += 1
    return cnt + cnt2 - 1

def cntright(y, x):
    cnt, cnt2 = 0, 0
    while get(y, x + cnt) == ' ': cnt += 1
    while get(y, x - cnt2) == ' ': cnt2 += 1
    return cnt + cnt2 - 1

def findhit():
    maxfound = 1
    result = []

    for y in range(10):
        for x in range(10):
            dres = cntdown(y, x)
            if dres > maxfound: maxfound, result = dres, []
            if dres == maxfound: result.append((y, x, 0))

            rres = cntright(y, x)
            if rres > maxfound: maxfound, result = rres, []
            if rres == maxfound: result.append((y, x, 1))

    y, x, _ = random.choice(result)
    return y, x

def place(y, x):
    global state

    outcome = input('({}) {}{}: '.format(state, y + 1, string.ascii_uppercase[x]))[0].lower()
    if outcome == 's':
        board[y][x] = '*'
        size = fill(y, x)
        if ships.count(size) == 0:
            raise ValueError("Sunk a non-existant ship")
        ships.pop(ships.index(size))
        state = 'find'
        print('Sunk of size {}'.format(size))
    elif outcome == 'h':
        board[y][x] = '*'
    elif outcome == 'm':
        board[y][x] = 'x'

    return outcome

ships = [4, 3, 3, 2, 2, 2, 1, 1, 1, 1]
board = [[' '] * 10 for x in range(10)]
state = 'find'
print("Outcomes: Hit, Miss, Sunk")

while ships:
    if state == 'find':
        y, x = findhit()
        if place(y, x) == 'h':
            state = 'dir'

    elif state == 'dir':
        result = around(y, x, False, [' '])
        if not result:
            raise ValueError("Impossible to place multi-part ship")
        yp, xp = result[0]
        if place(yp, xp) == 'h':
            goy = int(yp != y)
            gox = int(xp != x)
            state = 'hright'

    elif state == 'hright' or state == 'hleft':
        count = 1
        while get(y + count * goy, x + count * gox) in ['*', '@']:
            count += 1
        equals = get(y + count * goy, x + count * gox)
        if equals != ' ':
            if state == 'hleft':
                raise ValueError("Unsinkabble ship")
            state = 'hleft'
            goy *= -1
            gox *= -1
        elif place(y + count * goy, x + count * gox) == 's':
            state = 'find'

    pboard()

print("All enemy ships sank")
print("Total shots: {}".format(countf(['x', '@'])))
print("On target: {}".format(countf(['@'])))
print("Real misses: {}".format(countf(['x'])))
print("Avoided misses: {}".format(countf(['.'])))