View Compilation Error

0_0_20608899_10515.cpp: In function 'int main()':
0_0_20608899_10515.cpp:44:39: error: 'memset' was not declared in this scope
   t=check=0;memset(flag,0,sizeof(flag));
                                       ^
0_0_20608899_10515.cpp:53:19: error: 'sort' was not declared in this scope
       sort(a,a+t-1);
                   ^