#IMPLEMENT 3 STACKS IN A SINGLE ARRAY DRIVER#

#IMPLEMENT 3 STACKS IN A SINGLE ARRAY DRIVER#

* Driver program to test twStacks class */Ĭout << 'Popped element from stack1 is ' << ts.pop1() Ĭout << ' Popped element from stack2 is ' << ts. Method to pop an element from second stack There is at least one empty space for new element

This check is highlighted in the below code. To check for overflow, all we need to check is for space between top elements of both stacks. for implementing this first we will create two array arr of size n for storing values. In this method we will create array of some size and divide that array into k parts for storing elements of k stacks. Both stacks grow (or shrink) in opposite direction. Let us get started with Implement K stacks in one array. In this episode, we solve Cracking the Coding Interview problem Three in One where we are asked to describe how we can implement three stack using one array. Variables top1 and top2 (topl< top 2) point to the location of the topmost element in each of the stacks. The two stacks grow from opposite ends of the array. The stack2 starts from the rightmost corner, the first element in stack2 is pushed at index (n-1). A single array A1.MAXSIZE is used to implement two stacks. stack1 starts from the leftmost element, the first element in stack1 is pushed at index 0. The idea is to start two stacks from two extreme corners of arr. It doesn’t cause an overflow if there is space available in arr. This method efficiently utilizes the available space. One efficient way to implement k queues in a single array is to use a technique called circular array implementation of k queues. Here is the generalized, yet more specific definition: Implement a data structure MultiStack that uses a single array to implement arbitrary (N) number of stacks. Cracking the Coding Interview (6th edition) After some consideration I decided to reshape it. In addition to the array, you can use only O(1) additional space. Describe how you could use a single array to implement three stacks. Both push() and pop() operations should take O(1) time. As long as the sum of the three stack sizes is < N, push() should not fail.

Method 2 (A space efficient implementation) More specifically, is it possible to implement three stacks given the following conditions: You have a fixed size array that can hold N objects. When we push 4th element to stack1, there will be overflow even if we have space for 3 more elements in array.

For example, say the array size is 6 and we push 3 elements to stack1 and do not push anything to second stack2. A stack push operation may result in stack overflow even if there is space available in arr. The problem with this method is inefficient use of array space. Method 1 (Divide the space in two halves) (not the answer to above question as it can overflow even when number of elements isn't n)Ī simple way to implement two stacks is to divide the array in two halves and assign the half half space to two stacks, i.e., use arr to arr for stack1, and arr to arr for stack2 where arr is the array to be used to implement two stacks and size of array be n.

Implement 3 stacks in a single array