View Compilation Error

0_0_36795172_27253.cpp: In function 'void solve()':
0_0_36795172_27253.cpp:21:26: error: 'memset' was not declared in this scope
  memset(nxt,0,sizeof(nxt));
                          ^
0_0_36795172_27253.cpp: In function 'int main()':
0_0_36795172_27253.cpp:36:27: error: 'memset' was not declared in this scope
   memset(s+1,0,sizeof(s+1));
                           ^
0_0_36795172_27253.cpp:38:15: error: 'strlen' was not declared in this scope
   n=strlen(s+1);
               ^