View Compilation Error

0_0_36624563_17633.cpp: In function 'int main()':
0_0_36624563_17633.cpp:21:30: error: 'memset' was not declared in this scope
   memset(pre, -1, sizeof(pre));
                              ^
0_0_36624563_17633.cpp: In function 'int bfs(int, int)':
0_0_36624563_17633.cpp:65:36: error: 'memset' was not declared in this scope
  memset(visited, 0, sizeof(visited));
                                    ^