View Compilation Error

0_0_29705349_11343.cpp: In function 'int bfs()':
0_0_29705349_11343.cpp:14:32: error: 'memset' was not declared in this scope
     memset(pre, -1, sizeof(pre));
                                ^
0_0_29705349_11343.cpp: In function 'int main()':
0_0_29705349_11343.cpp:60:31: error: 'memset' was not declared in this scope
         memset(G, 0, sizeof(G));
                               ^