View Compilation Error

0_0_20538620_30473.cpp: In function 'int mex(int)':
0_0_20538620_30473.cpp:17:32: error: 'memset' was not declared in this scope
  memset(vis, false, sizeof(vis));
                                ^
0_0_20538620_30473.cpp: In function 'int main()':
0_0_20538620_30473.cpp:35:28: error: 'memset' was not declared in this scope
   memset(sg, -1, sizeof(sg));
                            ^