def decimal_to_binary(decimal_num):
# Handle zero edge case
if decimal_num == 0:
return "0"
is_negative = decimal_num < 0
decimal_num = abs(decimal_num)
binary_str = ""
while decimal_num > 0:
binary_str = str(decimal_num % 2) + binary_str
decimal_num //= 2
return "-" + binary_str if is_negative else binary_str
def binary_to_decimal(binary_str):
is_negative = binary_str.startswith('-')
if is_negative:
binary_str = binary_str[1:]
decimal_num = 0
for i, bit in enumerate(reversed(binary_str)):
if bit not in ('0', '1'):
raise ValueError("Binary string must contain only 0s and 1s")
decimal_num += int(bit) * (2 ** i)
return -decimal_num if is_negative else decimal_num
# 🔁 Test cases
test_decimals = [10, -10, 0, 255, -255]
test_binaries = ["1010", "-1010", "0", "11111111", "-11111111"]
print("📥 Decimal to Binary:")
for num in test_decimals:
print(f"{num} → {decimal_to_binary(num)}")
print("\n📤 Binary to Decimal:")
for bstr in test_binaries:
print(f"{bstr} → {binary_to_decimal(bstr)}")
📥 Decimal to Binary:
10 → 1010
-10 → -1010
0 → 0
255 → 11111111
-255 → -11111111
📤 Binary to Decimal:
1010 → 10
-1010 → -10
0 → 0
11111111 → 255
-11111111 → -255
import time
valid_difficulties = ["easy", "medium", "hard"]
difficulty = input("Enter difficulty (easy, medium, hard): ").lower().strip()
while difficulty not in valid_difficulties:
print("Please enter a valid difficulty level.")
time.sleep(0.5)
difficulty = input("Enter difficulty (easy, medium, hard): ").lower().strip()
print("✅ Difficulty set to:", difficulty)
✅ Difficulty set to: medium