Leaderboard
Showing:
Handle Score
@Ibrahim Nash 6420
@blackshadows 6380
@mb1973 5704
@Quandray 5245
@akhayrutdinov 5111
@saiujwal13083 5046
@sanjay05 3762
@kirtidee18 3673
@marius_valentin_dragoi 3523
@mantu_singh 3510
@sushant_a 3459
Complete Leaderboard
Implement two stacks in an array
Easy Accuracy: 49.76% Submissions: 49418 Points: 2

Your task is to implement  2 stacks in one array efficiently.

 

Example 1:

Input:
push1(2)
push1(3)
push2(4)
pop1()
pop2()
pop2()

Output:
3 4 -1

Explanation:
push1(2) the stack1 will be {2}
push1(3) the stack1 will be {2,3}
push2(4) the stack2 will be {4}
pop1()   the poped element will be 3 
from stack1 and stack1 will be {2}
pop2()   the poped element will be 4 
from stack2 and now stack2 is empty
pop2()   the stack2 is now empty hence -1 .

 

Your Task:
You don't need to read input or print anything. You are required to complete the 4 methods push1, push2 which takes one argument an integer 'x' to be pushed into stack one and two and pop1, pop2 which returns the integer poped out from stack one and two. If no integer is present in the array return -1.

 

Expected Time Complexity: O(1) for all the four methods.
Expected Auxiliary Space: O(1) for all the four methods.

 

Constraints:
1 <= Number of queries <= 100
1 <= value in the stack <= 100

The sum of elements in both the stacks < size of the given array

to report an issue on this page.

Editorial

We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?

Yes

All Submissions

My Submissions:

Login to access your submissions.

Implement two stacks in an array

Output Window