View Compilation Error

0_0_37137419_15879.cpp: In function 'void spfa(int)':
0_0_37137419_15879.cpp:10:38: error: 'memset' was not declared in this scope
 #define mem(a,b) memset(a,b,sizeof(a))
                                      ^
0_0_37137419_15879.cpp:53:2: note: in expansion of macro 'mem'
  mem(dis, -0x3f);
  ^
0_0_37137419_15879.cpp: In function 'int main()':
0_0_37137419_15879.cpp:10:38: error: 'memset' was not declared in this scope
 #define mem(a,b) memset(a,b,sizeof(a))
                                      ^
0_0_37137419_15879.cpp:89:3: note: in expansion of macro 'mem'
   mem(head, -1);
   ^