View Compilation Error

0_0_21812156_10558.cpp: In function 'int bfs()':
0_0_21812156_10558.cpp:48:24: error: 'memset' was not declared in this scope
  memset(dp,0,sizeof(dp));
                        ^
0_0_21812156_10558.cpp: In function 'int main()':
0_0_21812156_10558.cpp:193:30: error: 'memset' was not declared in this scope
   memset(head,-1,sizeof(head));
                              ^