- Write a program to determine whether a string is a valid bracket sequence.
def isValidParentheses(s):
stack = []
parentheses = {
')': '(', ']': '[', '}': '{'}
for char in s:
if char in parentheses.values():
stack.append(char)
elif char in parentheses.keys():
if len(stack) == 0 or parentheses[char] != stack.pop():
return False
return len(stack) == 0
string = input("请输入一个括号序列：")
if isValidParentheses(string):
print(string, "是有效的括号序列")
else:
print(string, "不是有效的括号序列")
- Write a program to calculate the factorial of a number.
num = int(input("请输入一个正整数："))
factorial = 1
for i in range(1, num+1):
factorial *= i
print(num, "的阶乘为：", factorial)
- Write a program that generates all prime numbers in a specified range.
start = int(input("请输入范围的起始值："))
end = int(input("请输入范围的结束值："))
prime_numbers = []
for num in range(start, end+1):
if num > 1:
for i in range(2, int(num/2)+1):
if (num % i) == 0:
break
else:
prime_numbers.append(num)
print("指定范围内的素数为：", prime_numbers)
- Write a program to determine whether a number is a palindrome.
num = int(input("请输入一个整数："))
if str(num) == str(num)[::-1]:
print(num, "是回文数")
else:
print(num, "不是回文数")
- Write a program to find all even numbers in a list.
num_list = [1, 2, 3, 4, 5, 6]
even_numbers = [num for num in num_list if num % 2 == 0]
print("列表中的偶数为：", even_numbers)
- Write a program that counts the number of occurrences of each word in a string.
string = input("请输入一个字符串：")
word_count = {
}
words = string.split()
for word in words:
word_count[word] = word_count.get(word, 0) + 1
print("每个单词出现的次数：")
for word, count in word_count.items():
print(word, ":", count)
- Write a program to find the two largest numbers in a list.
num_list = [10, 5, 8, 2, 15, 3]
sorted_list = sorted(num_list, reverse=True)
max_numbers = sorted_list[:2]
print("列表中的最大的两个数为：", max_numbers)
- Write a program that flips an integer and outputs it.
num = int(input("请输入一个整数："))
reversed_num = int(str(abs(num))[::-1])
if num < 0:
reversed_num *= -1
print("翻转后的整数为：", reversed_num)
- Write a program to determine whether a string is a palindrome.
string = input("请输入一个字符串：")
string = ''.join(char.lower() for char in string if char.isalpha())
if string == string[::-1]:
print("是回文句")
else:
print("不是回文句")
- Write a program that moves all even numbers in a list to the end of the list.
num_list = [1, 2, 3, 4, 5, 6]
odd_numbers = [num for num in num_list if num % 2 != 0]
even_numbers = [num for num in num_list if num % 2 == 0]
new_list = odd_numbers + even_numbers
print("移动后的列表为：", new_list)
Here is the code sample for questions 11 to 20. If you need more code for practice questions, please feel free to let me know.