SDE - 1

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 ]   ]

You have been given an array 'ARR' of 'N' distinct elements.

Your task is to find the minimum no. of swaps required to sort the array.

For example:

For the given input array [4, 3, 2, 1], the minimum no. of swaps required to sort the array is 2, i.e. swap index 0 with 3 and 1 with 2 to form the sorted array [1, 2, 3, 4].

You are given an array “Nums” of size ‘N’ and two numbers ‘L,’ ‘R.’ Your task is to return the number of range sum that lies between L and R, both inclusive, where L<=R.

Range sum R(i,j) represents the sum of numbers between the index i to j in Nums. where i <= j.

Example :

Let nums = [1, 2, 3], L = 2, R = 7

Then the possible ranges are [1,1],[2,2],[0,1],[1,2],[0,2], and their sum is 2,3,3,5,6 respectively. Hence the answer will be 5.

Note: Assume zero based indexing.

Design and implement a data structure for Least Recently Used (LRU) cache to support the following operations:

1. get(key) - Return the value of the key if the key exists in the cache, otherwise return -1.

2. put(key, value), Insert the value in the cache if the key is not already present or update the value of the given key if the key is already present. When the cache reaches its capacity, it should invalidate the least recently used item before inserting the new item.

You will be given ‘Q’ queries. Each query will belong to one of these two types:

Type 0: for get(key) operation.
Type 1: for put(key, value) operation.

Note :

1. The cache is initialized with a capacity (the maximum number of unique keys it can hold at a time).

2. Access to an item or key is defined as a get or a put operation on the key. The least recently used key is the one with the oldest access time.

Design a cab booking app for driverless cars

You are given 4 arrays 'ARR1’, 'ARR2’, 'ARR3’, 'ARR4’, each consists of ‘N’ numbers. Your task is to return the number of tuples (i, j, k, l) satisfying the following conditions:

0 <= i,j,k,l < ‘N’
ARR1[i] + ARR2[j] + ARR3[k] + ARR4[l] = 0.