View Compilation Error

0_0_33083420_29278.cpp: In function 'void solve()':
0_0_33083420_29278.cpp:23:28: error: 'sort' was not declared in this scope
     sort(t.begin(), t.end());
                            ^
0_0_33083420_29278.cpp:24:46: error: 'unique' was not declared in this scope
     int ans = 26 - (unique(t.begin(), t.end()) - t.begin());
                                              ^