View Compilation Error

0_0_39198621_19229.cpp: In function 'void times(long long int*, long long int*, long long int, long long int)':
0_0_39198621_19229.cpp:88:9: error: 'memset' was not declared in this scope
   88 |         memset(a1,0,sizeof(a1));
      |         ^~~~~~
0_0_39198621_19229.cpp:3:1: note: 'memset' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    2 | #include<cmath>
  +++ |+#include <cstring>
    3 | #define int long long
0_0_39198621_19229.cpp: In function 'int main()':
0_0_39198621_19229.cpp:145:9: error: 'reverse' was not declared in this scope
  145 |         reverse(u,u+n);
      |         ^~~~~~~