Topic: language-problem / Level: intermediate

• 1952. Write a program to find the longest sequence of consecutive integers in an array.
• 1953. Write a program to check if a string is a valid credit card number using Luhns algorithm.
• 1954. Write a program to implement a simple shopping cart system with user authentication.
• 1955. Write a program to check if a number is a palindromic number using a function.
• 1956. Write a program to calculate the area of a triangle given its base and height.
• 1957. Write a program to implement a basic online course management system.
• 1958. Write a program to check if a number is a perfect number by calculating the sum of its divisors.
• 1959. Write a program to find the first duplicate element in an array using a function.
• 1960. Write a program to implement a simple online ticket booking application.
• 1961. Write a program to check if a string is a valid binary number.
• 1962. Write a program to find the longest increasing subsequence in an array using dynamic programming.
• 1963. Write a program to check if a string is a valid URL using regular expressions.
• 1964. Write a program to implement a basic online voting system with a user interface.
• 1965. Write a program to check if a number is a triangular number using a function.
• 1966. Write a program to find the sum of all the even numbers in a given range.
• 1967. Write a program to implement a basic online shopping application with a shopping cart.
• 1968. Write a program to check if two strings are equal ignoring case and punctuation.
• 1969. Write a program to find the longest substring without repeating characters using a sliding window.
• 1970. Write a program to implement a simple online reservation system for events.
• 1971. Write a program to check if a number is a happy number using a set.
• 1972. Write a program to find the maximum product of any two numbers in an array.
• 1973. Write a program to check if a string contains valid XML tags using a stack.
• 1974. Write a program to implement a simple note-taking application that saves to a file.
• 1975. Write a program to check if a number is a Smith number using its prime factors.
• 1976. Write a program to find the longest common prefix among multiple strings.
• 1977. Write a program to implement a basic online bookstore with inventory tracking.
• 1978. Write a program to check if a string is a valid email address using regex.
• 1979. Write a program to find the first unique character in a string using a hash map.
• 1980. Write a program to implement a simple text-based adventure game.
• 1981. Write a program to check if a number is a prime number using the Sieve of Eratosthenes.
• 1982. Write a program to find the sum of the digits of a hexadecimal number.
• 1983. Write a program to implement a basic file compression utility.
• 1984. Write a program to check if a string contains balanced parentheses using recursion.
• 1985. Write a program to find the first duplicate character in a string using a function.
• 1986. Write a program to implement a basic online food ordering system.
• 1987. Write a program to check if a number is an odd composite number.
• 1988. Write a program to find the longest sequence of digits in a string.
• 1989. Write a program to implement a simple online journal.
• 1990. Write a program to check if a string can be rearranged to form a palindrome.
• 1991. Write a program to calculate the total distance traveled based on speed and time.
• 1992. Write a program to check if a number is a Kaprekar number.
• 1993. Write a program to find the longest common substring between two strings using dynamic programming.
• 1994. Write a program to implement a basic task scheduling application.
• 1995. Write a program to check if a string is a valid date in the format YYYY-MM-DD.
• 1996. Write a program to find the first non-repeating digit in a string.
• 1997. Write a program to implement a simple online chat application.
• 1998. Write a program to check if a number is a happy number using the tortoise and hare method.
• 1999. Write a program to find the maximum length of a palindromic substring in a string.
• 2000. Write a program to implement a basic online feedback system for products.
• 2001. Write a program to check if a string is a valid time in the format HH:MM

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