SDE - Intern

You are given a sorted doubly linked list of distinct nodes that means no two nodes present in the list have the same data. You are also given an integer 'X'.Your task is to count the number of triplets in the list that sum up to a given value 'X'.

A doubly linked List (DLL) contains an extra pointer, called the previous pointer, together with the next pointer and data, which are there in the singly linked list such that both forward and backward navigation is possible.

For example, DLL is 1<->2<->3<->4 NULL and the given integer 'X' is 9, then the number of triplets having the sum 9 is only one, and that is (2,3,4).

Note:

1. If no such triplets exist, return zero.
2. At least three elements will always be present in the linked list.

You have been given a non-empty grid consisting of only 0s and 1s. You have to find the number of islands in the given grid.

An island is a group of 1s (representing land) connected horizontally, vertically or diagonally. You can assume that all four edges of the grid are surrounded by 0s (representing water).

You are given an array of integers ARR[] of size N consisting of zeros and ones. You have to select a subset and flip bits of that subset. You have to return the count of maximum one’s that you can obtain by flipping chosen sub-array at most once.

A flip operation is one in which you turn 1 into 0 and 0 into 1.

For example:

If you are given an array {1, 1, 0, 0, 1} then you will have to return the count of maximum one’s you can obtain by flipping anyone chosen sub-array at most once, so here you will clearly choose sub-array from the index 2 to 3 and then flip it's bits. So, the final array comes out to be {1, 1, 1, 1, 1} which contains five ones and so you will return 5.