把一个数组分成三份，两个分割点不算进求和中，使得每份的和要相同

#include 
#include 
using namespace std;

int position(vector<int>sum, int i, int j, int len)
{
    int flag = 0;
    while (i < j)
    {

        if (iif (sum[len - 1] - sum[j] == sum[i] && sum[i] == sum[j - 1] - sum[i+1])
            {
                flag = 1;
                cout << i+1 << "   " << j << endl;
                break;
            }
        }
        --j;
    }

    return flag;
}

int main()
{
    //int a[] = {2,5,1,3,4,6,7};
    int n;
    while (cin >> n)
    {
        vector<int>a;
        for (int i = 0; i < n; ++i)
        {
            int tmp;
            cin >> tmp;
            a.push_back(tmp);
        }
        //---------分割线-------
        vector<int>sum;
        int s = 0;
        for (size_t i = 0; i < a.size(); ++i)
        {
            s += a[i];
            sum.push_back(s);
        }
        int len = sum.size();
        size_t i = 1, j = len - 2;
        for (; i < len; ++i)
        {
            int flag = position(sum, i, j, len);
            if (flag == 1)
                break;
        }
    }
    return 0;
}