View Compilation Error

0_0_22123958_8360.cpp: In function 'void bfs(long long int)':
0_0_22123958_8360.cpp:23:35: error: 'memset' was not declared in this scope
     memset(level, -1, sizeof level);
                                   ^
0_0_22123958_8360.cpp: In function 'int main()':
0_0_22123958_8360.cpp:100:37: error: 'memset' was not declared in this scope
         memset(head, -1, sizeof head);
                                     ^