View Compilation Error

0_0_30526357_5912.cpp: In function 'int dfs(int)':
0_0_30526357_5912.cpp:43:34: error: 'memset' was not declared in this scope
     memset(link, -1, sizeof(link));
                                  ^
0_0_30526357_5912.cpp: In function 'int main(int, const char**)':
0_0_30526357_5912.cpp:59:31: error: 'memset' was not declared in this scope
         memset(g, 0, sizeof(g));
                               ^