More Problems

• Write a program to find the longest substring with at most k distinct characters.
• Write a program to implement a simple online exam platform with timed quizzes.
• Write a program to check if a binary tree is a valid binary search tree.
• Write a program to find the total number of unique characters in a string.
• Write a program to implement a basic online file sharing service.
• Write a program to check if a string contains only balanced parentheses.
• Write a program to find the first character that is not repeated in a string.
• Write a program to implement the counting sort algorithm.