3. Write a Python class to find validity of a string of parentheses, '(', ')', '{', '}', '[' and ']. These brackets must be close in the correct order, for example "()" and "()[]{}" are valid but "[)", "({[)]" and "{{{" are invalid. - Go to the editor

4. Write a Python class to get all possible unique subsets from a set of distinct integers. - Go to the editor
Input : [4, 5, 6]
Output : [[], [6], [5], [5, 6], [4], [4, 6], [4, 5], [4, 5, 6]]

5. Write a Python class to find a pair of elements (indices of the two numbers) from a given array whose sum equals a specific target number. - Go to the editor
Input: numbers= [10,20,10,40,50,60,70], target=50
Output: 3, 4

6. Write a Python class to find the three elements that sum to zero from a set of n real numbers. - Go to the editor
Input array : [-25, -10, -7, -3, 2, 4, 8, 10]
Output : [[-10, 2, 8], [-7, -3, 10]]

9. Write a Python class which has two methods get_String and print_String. get_String accept a string from the user and print_String print the string in upper case. - Go to the editor Click me to see the solution

11. Write a Python class named Circle constructed by a radius and two methods which will compute the area and the perimeter of a circle. - Go to the editor Click me to see the solution

12. Write a Python class named Circle constructed by a radius and two methods which will compute the area and the perimeter of a circle. - Go to the editor Click me to see the solution