View Compilation Error

0_0_37586421_29615.cpp: In function 'int solve()':
0_0_37586421_29615.cpp:10:41: error: 'memset' was not declared in this scope
 #define mem(a, b) memset(a, b, sizeof(a))
                                         ^
0_0_37586421_29615.cpp:30:2: note: in expansion of macro 'mem'
  mem(col,0);
  ^
0_0_37586421_29615.cpp: In function 'int main()':
0_0_37586421_29615.cpp:10:41: error: 'memset' was not declared in this scope
 #define mem(a, b) memset(a, b, sizeof(a))
                                         ^
0_0_37586421_29615.cpp:60:3: note: in expansion of macro 'mem'
   mem(col,0);
   ^