SPbCTF - iZba

solve.py

import sys
import random

import requests


http = requests.Session()
http.cert = 'client.pem'
base_url = 'https://its-izba-4ncvjm8.spbctf.ru:13443'

uuid = http.get(f'{base_url}/init').json()['uuid']


class pos:
    x = 0
    y = 0


m = {}  # map
bounds = [-1, -1, 1, 1]


def step(dx, dy):
    if pos.x + dx <= bounds[0]:
        bounds[0] = pos.x + dx - 1
    if pos.x + dx >= bounds[2]:
        bounds[2] = pos.x + dx + 1
    if pos.y + dy <= bounds[1]:
        bounds[1] = pos.y + dy - 1
    if pos.y + dy >= bounds[3]:
        bounds[3] = pos.y + dy + 1
    resp = http.post(f'{base_url}/step/{uuid}', data=f'{dx} {dy}')
    resp.raise_for_status()
    d = resp.json()
    if 'flag' in d:
        print(d['flag'])
        sys.exit(0)
    if pos.x == d['firstCoordinate'] and pos.y == d['secondCoordinate']:
        m[(pos.x + dx, pos.y + dy)] = '#'
        return False
    else:
        m[(pos.x + dx, pos.y + dy)] = ' '
        assert pos.x + dx == d['firstCoordinate']
        assert pos.y + dy == d['secondCoordinate']
        pos.x = d['firstCoordinate']
        pos.y = d['secondCoordinate']
        return True


def draw_map():
    sys.stdout.write("\033c")
    for x in range(bounds[0], bounds[2] + 1):
        print(''.join(
            m.get((x, y), '?') if (x, y) != (pos.x, pos.y) else '*'
            for y in range(bounds[1], bounds[3] + 1)
        ))
    print()


def depth_first_walk(visited=set()):
    draw_map()
    moves = [(0, -1), (1, 0), (0, 1), (-1, 0)]
    random.shuffle(moves)
    for dx, dy in moves:
        if (pos.x + dx, pos.y + dy) not in visited:
            visited.add((pos.x, pos.y))
            if step(dx, dy):
                depth_first_walk()
                step(-dx, -dy)


depth_first_walk(set([(0, 0)]))