View Compilation Error

0_0_31235495_16471.cpp: In function 'bool check(int, int, int)':
0_0_31235495_16471.cpp:37:38: error: 'memset' was not declared in this scope
 #define MEM(a,x) memset(a,x,sizeof(a))
                                      ^
0_0_31235495_16471.cpp:169:5: note: in expansion of macro 'MEM'
     MEM(vis,0);
     ^
0_0_31235495_16471.cpp: In function 'int main()':
0_0_31235495_16471.cpp:247:29: error: 'strlen' was not declared in this scope
             len = strlen(str);
                             ^