Buggy python submission (verdict: Runtime Error):
import sys

N = int(sys.stdin.readline())
D = list(map(int, sys.stdin.readline().split()))

times = [0] * 24
for d in D:
    times[d] += 1

if max(times) > 2 or times[0] == 2 or times[12] == 2:
    print(0)
else:
    ans = 0
    # 1 - 11時間の時差の場合、Diと24 - Diの両方を試す
    for i in range(2**11):
        positions = []
        if times[0] == 1:
            positions.append(0)
        for j in range(11):
            if times[j+1] == 2:
                positions.append(j+1)
                positions.append(24 - j-1)
            elif times[j+1] == 1:
                if (i >> j) & 1:
                    positions.append(24 - j-1)
                else:
                    positions.append(j+1)
        if times[12] == 1:
            positions.append(12)
        positions.sort()
        # print(positions)
        lp = len(positions)
        d = float("inf")
        for p in range(lp):
            # 0をまたぐ場合がある
            if p == lp -1:
                diff = 24 - positions[p] + positions[0]
            else:
                diff = positions[p+1] - positions[p]
            d = min(d, diff if diff != 24 else 0)
        ans = max(ans, d)

print(ans)

Fixed submission:
import sys

N = int(sys.stdin.readline())
D = list(map(int, sys.stdin.readline().split()))

times = [0] * 24
times[0] = 1
for d in D:
    times[d] += 1

if max(times) > 2 or times[0] == 2 or times[12] == 2:
    print(0)
else:
    ans = 0
    # 1 - 11時間の時差の場合、Diと24 - Diの両方を試す
    for i in range(2**11):
        positions = [0]
        for j in range(1, 12):
            if times[j] == 2:
                positions.append(j)
                positions.append(24 - j)
            elif times[j] == 1:
                if (i >> j) & 1:
                    positions.append(24 - j)
                else:
                    positions.append(j)
        if times[12] == 1:
            positions.append(12)
        positions.sort()
        # print(positions)
        lp = len(positions)
        d = float("inf")
        for p in range(lp):
            # 0をまたぐ場合がある
            if p == lp -1:
                diff = 24 - positions[p] + positions[0]
            else:
                diff = positions[p+1] - positions[p]
            d = min(d, diff if diff != 24 else 0)
        ans = max(ans, d)

    print(ans)

Buggy python submission (verdict: Runtime Error):
import sys

N = int(sys.stdin.readline())
D = list(map(int, sys.stdin.readline().split()))

times = [0] * 24
for d in D:
    times[d] += 1

if max(times) > 2 or times[0] == 2 or times[12] == 2:
    print(0)
else:
    ans = 0
    # 1 - 11時間の時差の場合、Diと24 - Diの両方を試す
    for i in range(2**11):
        positions = []
        if times[0] == 1:
            positions.append(0)
        for j in range(11):
            if times[j+1] == 2:
                positions.append(j+1)
                positions.append(24 - j-1)
            elif times[j+1] == 1:
                if (i >> j) & 1:
                    positions.append(24 - j-1)
                else:
                    positions.append(j+1)
        if times[12] == 1:
            positions.append(12)
        positions.sort()
        # print(positions)
        lp = len(positions)
        d = float("inf")
        for p in range(lp):
            # 0をまたぐ場合がある
            diff = abs(positions[(p+1) % lp] - positions[p])
            d = min(d, diff)
        ans = max(ans, d)

print(ans)

Fixed submission:
import sys

N = int(sys.stdin.readline())
D = list(map(int, sys.stdin.readline().split()))

times = [0] * 24
times[0] = 1
for d in D:
    times[d] += 1

if max(times) > 2 or times[0] == 2 or times[12] == 2:
    print(0)
else:
    ans = 0
    # 1 - 11時間の時差の場合、Diと24 - Diの両方を試す
    for i in range(2**11):
        positions = [0]
        for j in range(1, 12):
            if times[j] == 2:
                positions.append(j)
                positions.append(24 - j)
            elif times[j] == 1:
                if (i >> j) & 1:
                    positions.append(24 - j)
                else:
                    positions.append(j)
        if times[12] == 1:
            positions.append(12)
        positions.sort()
        # print(positions)
        lp = len(positions)
        d = float("inf")
        for p in range(lp):
            # 0をまたぐ場合がある
            if p == lp -1:
                diff = 24 - positions[p] + positions[0]
            else:
                diff = positions[p+1] - positions[p]
            d = min(d, diff if diff != 24 else 0)
        ans = max(ans, d)

    print(ans)