Topic: language-problem / Level: intermediate

• 1802. Write a program to find the longest substring without repeating characters using a sliding window approach.
• 1803. Write a program to check if a number is a perfect number by calculating the sum of its divisors.
• 1804. Write a program to implement a simple online bookstore with search functionality.
• 1805. Write a program to calculate the total sales for each product in a sales report.
• 1806. Write a program to check if a string contains valid XML tags using a stack.
• 1807. Write a program to find the maximum length of a palindromic substring in a string.
• 1808. Write a program to implement a basic online course management system with user authentication.
• 1809. Write a program to check if a number is a palindromic number using a function.
• 1810. Write a program to calculate the area of an ellipse given the semi-major and semi-minor axes.
• 1811. Write a program to find the first unique digit in a number.
• 1812. Write a program to implement a simple inventory management system with restocking capabilities.
• 1813. Write a program to check if a string can be rearranged to form a palindrome.
• 1814. Write a program to find the total number of unique words in a text file.
• 1815. Write a program to calculate the sum of the first n odd Fibonacci numbers.
• 1816. Write a program to implement a basic note-taking application with file storage.
• 1817. Write a program to check if two strings are equal ignoring punctuation and case.
• 1818. Write a program to find the maximum product of any two distinct elements in an array.
• 1819. Write a program to implement a simple online quiz application with timed questions.
• 1820. Write a program to check if a number is a narcissistic number using its digits.
• 1821. Write a program to find the longest palindrome substring using the expand around center approach.
• 1822. Write a program to check if a number is an abundant number using a function.
• 1823. Write a program to implement a basic character frequency analyzer.
• 1824. Write a program to find the first character that appears more than once in a string.
• 1825. Write a program to check if a string is a valid credit card number using the Luhn algorithm.
• 1826. Write a program to calculate the average of a list of numbers using pointers.
• 1827. Write a program to implement a simple to-do list application with task prioritization.
• 1828. Write a program to find the total number of lines in a text file.
• 1829. Write a program to check if a number is a happy number using the tortoise and hare algorithm.
• 1830. Write a program to implement a basic online attendance management system.
• 1831. Write a program to check if two strings are anagrams using character frequency.
• 1832. Write a program to find the sum of all the unique elements in an array.
• 1833. Write a program to check if a string is a valid time in the format HH:MM
• 1834. Write a program to implement a simple character encoding and decoding utility.
• 1835. Write a program to calculate the surface area of a cone using its radius and height.
• 1836. Write a program to check if a string contains balanced parentheses using recursion.
• 1837. Write a program to implement a simple online feedback system for products.
• 1838. Write a program to find the longest increasing subsequence in a sequence of numbers.
• 1839. Write a program to check if a number is a strong number using a function.
• 1840. Write a program to implement a basic quiz application with scoring and feedback.
• 1841. Write a program to find the maximum frequency of any digit in a number.
• 1842. Write a program to check if a string is a valid hex color code using regex.
• 1843. Write a program to find the total number of palindromic substrings in a string.
• 1844. Write a program to implement a simple online bookstore with a shopping cart.
• 1845. Write a program to check if a number is a perfect number using a function.
• 1846. Write a program to calculate the average of numbers in a file.
• 1847. Write a program to find the smallest prime factor of a number using trial division.
• 1848. Write a program to implement a basic online recipe management system.
• 1849. Write a program to check if two strings can be made equal with limited character swaps.
• 1850. Write a program to find the first unique word in a sentence.
• 1851. Write a program to implement a simple weather forecasting application.

• More Levels

• Beginner
• Advanced