View Compilation Error

0_0_28554127_18908.cpp: In function 'void init()':
0_0_28554127_18908.cpp:16:36: error: 'memset' was not declared in this scope
     memset(first, -1, sizeof(first));
                                    ^
0_0_28554127_18908.cpp: In function 'int main()':
0_0_28554127_18908.cpp:67:43: error: 'memset' was not declared in this scope
             memset(visit, 0, sizeof(visit));
                                           ^