View Compilation Error

0_0_36041746_6057.cpp:59:92: error: 'matroid_insec' function uses 'auto' type specifier without trailing return type
 auto matroid_insec(int siz, const vector<int> &w, const VecSpace &m1, const GreedyLimit &m2) {
                                                                                            ^
0_0_36041746_6057.cpp:59:92: note: deduced return type only available with -std=c++1y or -std=gnu++1y