View Compilation Error

0_0_36440627_6816.cpp: In function 'bool bfs()':
0_0_36440627_6816.cpp:35:27: error: 'memset' was not declared in this scope
     memset(d, 0, sizeof(d));
                           ^
0_0_36440627_6816.cpp: In function 'int main()':
0_0_36440627_6816.cpp:90:38: error: 'memset' was not declared in this scope
         memset(head, -1, sizeof(head));
                                      ^