Ruudukko

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

n, m = map(int, input().split())
rivit = [0] * (n+2)
for i in range(m):
    y1, x1, y2, x2 = map(int, input().split())
    rivit[y1] ^= 1 << x1
    rivit[y1] ^= 1 << (x2 + 1)
    rivit[y2 + 1] ^= 1 << x1
    rivit[y2 + 1] ^= 1 << (x2 + 1)

rivi = 0
for i in range(1, n+1):
    rivi ^= rivit[i]
    x = 0
    for j in range(1, n+1):
        if rivi & (1 << j):
            x ^= 1
        print(".#"[x], end="")
    print()

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: ACCEPTED

Test 3

Group: 2, 3

Verdict: ACCEPTED

Test 4

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 5

Group: 3

Verdict: TIME LIMIT EXCEEDED