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 <iostream>#include <vector>using namespace std;int position(vector<int>sum, int i, int j, int len){    int flag = 0;    while (i < j)    {        if (i<j&&j<len)        {            if (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;}