int getSum(vector<int> h);

int equalStacks(vector<int> h1, vector<int> h2, vector<int> h3) {      
    int h1sum = getSum(h1);
    int h2sum = getSum(h2);
    int h3sum = getSum(h3);
    
    while (h1.size() && h2.size() && h3.size() && !(h1sum == h2sum && h1sum == h3sum)) {
        auto maxVal = max({ h1sum, h2sum, h3sum });
        if (maxVal == h1sum) {
            h1sum -= h1.at(0);
            h1.erase(h1.begin());
        }
        else if (maxVal == h2sum) {
            h2sum -= h2.at(0);
            h2.erase(h2.begin());
        }
        else {
            h3sum -= h3.at(0);
            h3.erase(h3.begin());
        }
    }

    if (h1.size() && h2.size() && h3.size()) {
        return h1sum;
    }
    else {
        return 0;
    }
}

int getSum(vector<int> h){
   return accumulate(h.begin(), h.end(), 0); 
}