Data Structure Array: Largest subarray with equal number of 0s and 1s

http://www.geeksforgeeks.org/largest-subarray-with-equal-number-of-0s-and-1s/

 #include <iostream>
 #include <vector>
 #include <algorithm>
 #include <queue>
 #include <stack>
 #include <string>
 #include <fstream>
 #include <map>
 using namespace std;

 void findsubarray(int arr[], int n) {
     map<int, vector<int> > S;
     int sum = ;
     for (int i = ; i < n; i++) {
         sum += (arr[i] == ? - : );
         if (S.find(sum) != S.end()) S[sum].push_back(i);
         else S[sum] = vector<int>(, i);
     }
     int ans = ;
     for (map<int, vector<int> >::iterator it = S.begin(); it != S.end(); it++) {
         if ((it->first) == ) ans = max(ans, (it->second)[(it->second).size()-]+);
         else ans = max(ans, (it->second)[(it->second).size()-] - (it->second)[]);
     }
     cout << ans << endl;
 }

 int main() {
     int arr[] = {, , , , , , };
     findsubarray(arr, );
     return ;
 }