Geeksforgeeks

Error

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

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Implement two stacks in an array

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