View Compilation Error

0_0_37657034_29483.cpp: In function 'int mex(int)':
0_0_37657034_29483.cpp:14:30: error: 'memset' was not declared in this scope
     memset(vis, 0, sizeof vis);
                              ^
0_0_37657034_29483.cpp: In function 'int main()':
0_0_37657034_29483.cpp:34:31: error: 'memset' was not declared in this scope
         memset(sg,-1,sizeof sg);
                               ^