SDE - Intern

Given three filled stacks namely ‘stack1’ ‘stack2’ and ‘stack3’ of positive numbers, the task is to find the possible equal maximum sum of the stacks with the removal of top elements allowed.

For example, let the stacks be:

We can see that currently,

the sum of stack 1 is: 8+5+3 = 16

the sum of stack 2 is: 2+2+4+9+6 = 23

the sum of stack 3 is: 2+1+2+3 = 8

So they are not equal.

However, if we pop {8} from stack 1, {6,9} from stack 2 and nothing from stack 3,

We get the sum as :

Stack 1: 16-8=8

Stack 2: 23-15=8

Stack 3: 8-0=8

We can see that now the sum of all three stacks are equal which is 8 and it is the highest possible, hence we return 8.

Note:

1. Do not print anything, just return an integer which is the maximum possible sum for the three stacks.
2.It is guaranteed that the elements in the stack are positive integers.
3.It can be proved that a non-negative integer answer always exists.