求以下python问题的解答

Question

初学python，上节课没有仔细听，麻烦帮忙看看指点一下谢谢

Answer 1

# 2-a
x=0
if x <= 0:
    print(x)
# 2-b
x = 0
y = 0  # 初始化 y
if 1 + x > x ** 2:
    y = y + x
# 2-c
x, y = 0, 1
if x == 1:
    y += 1
# 2-d
xStr = input("Enter an integer value:")
sum = 0
if xStr.isdigit():
    x = int(xStr)
    sum = sum + x
else:
    print("Bad input for x")

### 4
balance = 10_0000  # 存入10万元
interest_rate = 0.03  # 年利率3%
years = 0

while balance < 20_0000:
    balance += balance * interest_rate
    years += 1

print(f"需要{years}年，存款可以达到20万元。")


### 第六题
number = input("Enter an integer: ")
previous_digit = None
duplicates = []

for digit in number:
    if digit == previous_digit and digit not in duplicates:
        duplicates.append(digit)
    previous_digit = digit

print("Duplicates found:", " ".join(duplicates))

### 第五题
num = input("Enter a 4-digit number: ")
if len(num) != 4:
    print("Invalid input! Please enter a 4-digit number.")
else:
    if num[0] == num[1] and num[2] == num[3] and num[0] != num[2]:
        print("两对")
    elif num[0] == num[2] and num[1] == num[3] and num[0] != num[1]:
        print("两对")
    elif num[0] == num[3] and num[1] == num[2] and num[0] != num[1]:
        print("两对")
    else:
        print("不是两对")


### 3-a
运行结果是-1，因为n和m都是整数，n的值为1，m的值为-1，-1比1小，所以输出m的值-1