View Compilation Error

0_0_13830224_29710.cpp: In function 'void init()':
0_0_13830224_29710.cpp:20:25: error: 'memset' was not declared in this scope
     memset(G,0,sizeof(G));
                         ^
0_0_13830224_29710.cpp: In function 'void work(double)':
0_0_13830224_29710.cpp:51:28: error: 'memset' was not declared in this scope
     memset(tt,-1,sizeof(tt));
                            ^
0_0_13830224_29710.cpp: In function 'int get_rot(int*)':
0_0_13830224_29710.cpp:72:29: error: 'memset' was not declared in this scope
     memset(vis,0,sizeof(vis));
                             ^