Find_maximum_sum_possible_equal_sum_of_three_stacks.cpp

#include <bits/stdc++.h>
using namespace std;

int maxSum(int s1[], int s2[], int s3[], int n1, int n2, int n3)
{
    int sum1 = 0, sum2 = 0, sum3 = 0;
    int top1 = 0, top2 = 0, top3 = 0;
    int answer = 0;

    for (int i = 0; i < n1; i++)
        sum1 += s1[i];
    for (int i = 0; i < n2; i++)
        sum2 += s2[i];
    for (int i = 0; i < n3; i++)
        sum3 += s3[i];

    while (true)
    {
        // The condition when we have not find any sum.
        if (top1 == n1 || top2 == n2 || top3 == n3)
        {
            answer = 0;
            break;
        }

        else if (sum1 == sum2 and sum2 == sum3)
        {
            answer = sum1;
            break;
        }

        // The condition when sum1 is largest, then
        // subtract its top from the sum and shift the top
        else if (sum1 >= sum2 and sum1 >= sum3)
            sum1 -= s1[top1++];

        // The condition when sum2 is largest
        else if (sum2 >= sum3 and sum2 >= sum1)
            sum2 -= s2[top2++];

        // The condition when sum3 is largest
        else if (sum3 >= sum1 and sum3 >= sum2)
            sum3 -= s3[top3++];
    }
    return answer;
}

int main()
{
    int s1[] = {3, 2, 1, 1, 1};
    int s2[] = {4, 3, 2};
    int s3[] = {1, 1, 4, 1};

    int n1 = sizeof(s1) / sizeof(s1[0]);
    int n2 = sizeof(s2) / sizeof(s2[0]);
    int n3 = sizeof(s3) / sizeof(s3[0]);

    cout << "Maximum sum possible is : " << maxSum(s1, s2, s3, n1, n2, n3) << endl;

    return 0;
}