View Compilation Error

0_0_36630322_18976.cpp: In function 'int solve(int)':
0_0_36630322_18976.cpp:11:40: error: 'memset' was not declared in this scope
  int vis[2005]; memset(vis,0,sizeof vis);
                                        ^
0_0_36630322_18976.cpp: In function 'int main()':
0_0_36630322_18976.cpp:24:24: error: 'memset' was not declared in this scope
  memset(sg,-1,sizeof sg); sg[0] = 0; //记忆化查找
                        ^