View Compilation Error

0_0_21860858_19989.cpp: In function 'void check_dup(std::vector<Edge>&)':
0_0_21860858_19989.cpp:76:26: error: 'sort' was not declared in this scope
   sort(E.begin(), E.end());
                          ^
0_0_21860858_19989.cpp: In function 'int main()':
0_0_21860858_19989.cpp:86:18: error: 'scanf' was not declared in this scope
   scanf("%d", &tn);
                  ^
0_0_21860858_19989.cpp:110:36: error: 'printf' was not declared in this scope
     printf("%d %d\n", cost, idx + 1);
                                    ^