SDE - Intern

Ninja has been asked to organize a dance competition. Ninja decided that he will take individual entries and then will divide them into pairs. As part of the entry, he asked the participants to choose any number.

Ninja then thought of a creative method to divide them into pairs. He decided that he would select a number ‘K’, and then select numbers from the list that have a difference equal to ‘K’.

You need to help Ninja in finding the number of distinct pairs from the numbers with differences equal to ‘K’.

Example:

Let us suppose the numbers are chosen by participants: [2, 6, 5, 2, 3] and K = 3, then the distinct pairs having differences equal to K are: [2, 5] and [3, 6] so print 2. 

Note:

The list of numbers can contain duplicate numbers, you need to print only the distinct pairs.

For example [2, 2, 3, 4] and K = 1, so you need to print 2 as the two distinct pairs are: (2, 3) and (3, 4).

You are given two strings 'A' and 'B' where string 'A' is fixed. But you can perform left shift operations on string B any number of times.

Your task is to find out the minimum number of left-shift operations required in order to obtain the longest common prefix of string 'A' and 'B'.

Note:

Left shift is defined as a single circular rotation on the string after which the first character becomes the last character and all other characters are shifted one index to the left.

For Example:

If A = “an”, B = “can”.
After performing one left shift operation, string B becomes “anc”.
After performing two left shift operations, string B becomes “nca”.

Follow Up:

Can you solve this in linear time and space complexity?

You are given a square matrix of non-negative integers 'MATRIX'. Your task is to rotate that array by 90 degrees in an anti-clockwise direction using constant 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 ]   ]

You have been given an array/list 'arr' consisting of 'n' elements.

Each element in the array is either 0, 1 or 2.

Sort this array/list in increasing order.

Do not make a new array/list. Make changes in the given array/list.

Example :

Input: 'arr' = [2, 2, 2, 2, 0, 0, 1, 0]

Output: Final 'arr' = [0, 0, 0, 1, 2, 2, 2, 2]

Explanation: The array is sorted in increasing order.

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).