SDE - 1

Given a singly linked list, you have to detect the loop and remove the loop from the linked list, if present. You have to make changes in the given linked list itself and return the updated linked list.

Expected Complexity: Try doing it in O(n) time complexity and O(1) space complexity. Here, n is the number of nodes in the linked list.

You have been given an integer array/list(arr) and a number 'Sum'. Find and return the total number of pairs in the array/list which when added, results equal to the 'Sum'.

Note:

Given array/list can contain duplicate elements.

(arr[i],arr[j]) and (arr[j],arr[i]) are considered same.

You have been given a linked list of integers. Your task is to write a function that deletes a node from a given position, 'POS'.

Note :

Assume that the Indexing for the linked list always starts from 0.

If the position is greater than or equal to the length of the linked list, you should return the same linked list without any change.

Illustration :

The following images depict how the deletion has been performed.

Image-I :

Image-II :

You are given a square matrix of non-negative integers of size 'N x N'. Your task is to rotate that array by 90 degrees in an anti-clockwise direction without using any extra space.

For example:

For given 2D array :

    [    [ 1,  2,  3 ],
         [ 4,  5,  6 ],
         [ 7,  8,  9 ]  ]

After 90 degree rotation in anti clockwise direction, it will become:

    [   [ 3,  6,  9 ],
        [ 2,  5,  8 ],
        [ 1,  4,  7 ]   ]