SDE - 1

You are given an array 'arr' of size 'n' having unique elements that has been sorted in ascending order and rotated between 1 and 'n' times which is unknown.

The rotation involves shifting every element to the right, with the last element moving to the first position. For example, if 'arr' = [1, 2, 3, 4] was rotated one time, it would become [4, 1, 2, 3].

Your task is to find the minimum number in this array.

Note :

All the elements in the array are distinct. 

Example :

Input: arr = [3,4,5,1,2]

Output: 1

Explanation: The original array was [1,2,3,4,5] and it was rotated 3 times.

You are given a string, ‘S’. You need to reverse the string where characters that are not an alphabet stay in the same place, and the rest reverse their positions.

Eg: “a-bcd” becomes “d-cba”

You are given an array 'ARR' of 'N' distinct positive integers. You are also given a non-negative integer 'B'.

Your task is to return all unique combinations in the array whose sum equals 'B'. A number can be chosen any number of times from the array 'ARR'.

Elements in each combination must be in non-decreasing order.

For example:

Let the array 'ARR' be [1, 2, 3] and 'B' = 5. Then all possible valid combinations are-

(1, 1, 1, 1, 1)
(1, 1, 1, 2)
(1, 1, 3)
(1, 2, 2)
(2, 3)

You are given a 2D array with dimensions ‘N*M’. You need to read the array elements row-wise and return a linear array that stores the elements like a wave i.e the 1st-row elements are stored from left to right, 2nd-row elements are stored from right to left, and so on.

Implement a Stack Data Structure specifically to store integer data using two Queues.

There should be two data members, both being Queues to store the data internally. You may use the inbuilt Queue.

Implement the following public functions :

1. Constructor:
It initializes the data members(queues) as required.

2. push(data) :
This function should take one argument of type integer. It pushes the element into the stack and returns nothing.

3. pop() :
It pops the element from the top of the stack and, in turn, returns the element being popped or deleted. In case the stack is empty, it returns -1.

4. top :
It returns the element being kept at the top of the stack. In case the stack is empty, it returns -1.

5. size() :
It returns the size of the stack at any given instance of time.

6. isEmpty() :
It returns a boolean value indicating whether the stack is empty or not.

Operations Performed on the Stack:

Query-1(Denoted by an integer 1): Pushes an integer data to the stack. (push function)

Query-2(Denoted by an integer 2): Pops the data kept at the top of the stack and returns it to the caller. (pop function)

Query-3(Denoted by an integer 3): Fetches and returns the data being kept at the top of the stack but doesn't remove it, unlike the pop function. (top function)

Query-4(Denoted by an integer 4): Returns the current size of the stack. (size function)

Query-5(Denoted by an integer 5): Returns a boolean value denoting whether the stack is empty or not. (isEmpty function)

Example

Operations: 
1 5
1 10
2
3
4

Enqueue operation 1 5: We insert 5 at the back of the queue.
  Queue: [5]

Enqueue operation 1 10: We insert 10 at the back of the queue.
  Queue: [5, 10]

Dequeue operation 2: We remove the element from the front of the queue, which is 5, and print it.
  Output: 5
  Queue: [10]

Peek operation 3: We return the element present at the front of the queue, which is 10, without removing it.
  Output: 10
  Queue: [10]

IsEmpty operation 4: We check if the queue is empty.
  Output: False
  Queue: [10]

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

1. Push(num): Push the given number in the stack.
2. Pop: Remove and return the top element from the stack if present, else return -1.
3. Top: return the top element of the stack if present, else return -1.
4. getMin: Returns minimum element of the stack if present, else return -1.

For Example:

For the following input: 
1
5
1 1
1 2
4
2
3

For the first two operations, we will just insert 1 and then 2 into the stack which was empty earlier. So now the stack is => [2,1]
In the third operation, we need to return the minimum element of the stack, i.e., 1. So now the stack is => [2,1]
For the fourth operation, we need to pop the topmost element of the stack, i.e., 2. Now the stack is => [1]
In the fifth operation, we return the top element of the stack, i.e. 1 as it has one element. Now the stack is => [1]

So, the final output will be: 
1 2 1

You have been given an integer array/list (ARR) of size N. You have to return an array/list PRODUCT such that PRODUCT[i] is equal to the product of all the elements of ARR except ARR[i]

 Note :

Each product can cross the integer limits, so we should take modulo of the operation. 

Take MOD = 10^9 + 7 to always stay in the limits.

Follow up :

Can you try solving the problem in O(1) space?