Monikulmio

def sign(x):
    if x > 0:
        return 1
    if x < 0:
        return -1
    return 0

height, width, cornerCount = (int(x) for x in input().split())
corners = [tuple(int(x) - 1 for x in input().split()) for _ in range(cornerCount)]

grid = [["#" for _ in range(width)] for _ in range(height)]

prev_y, prev_x = corners[-1]
for (y, x) in corners:
    dy = y - prev_y
    dx = x - prev_x
    char = "?"
    match (sign(dy), sign(dx)):
        case (1, 1) | (-1, -1):
            char = "\\"
        case (1, -1) | (-1, 1):
            char = "/"
        case (0, 1) | (0, -1):
            char = "="
        case (1, 0) | (-1, 0):
            char = "|"
    
    for t in range(1, max(abs(dy), abs(dx))):
        grid[prev_y + sign(dy) * t][prev_x + sign(dx) * t] = char
    
    grid[y][x] = "*"
    prev_y, prev_x = y, x


chars = ('#', '.')
for row in grid:
    for (i, cell) in enumerate(row):
        if cell in chars:
            row[i] = '.'
        else:
            break
    for (i, cell) in enumerate(reversed(row)):
        if cell in chars:
            row[-1 - i] = '.'
        else:
            break

for i in range(width):
    for row in grid:
        if row[i] in chars:
            row[i] = '.'
        else:
            break
    for row in reversed(grid):
        if row[i] in chars:
            row[i] = '.'
        else:
            break
        

for row in grid:
    print("".join(row))

Test 1 (public)

Verdict: ACCEPTED

Test 2 (public)

Verdict: ACCEPTED

Test 3 (public)

Verdict: ACCEPTED

Test 4 (public)

Verdict: ACCEPTED

Test 5 (public)

Verdict: ACCEPTED

Test 6 (public)

Verdict: ACCEPTED

Test 7 (public)

Verdict: ACCEPTED

Test 8 (public)

Verdict: ACCEPTED

Test 9 (public)

Verdict: ACCEPTED

Test 10 (public)

Verdict: ACCEPTED