View Compilation Error

0_0_18470823_6302.cpp: In function 'void init()':
0_0_18470823_6302.cpp:12:28: error: 'memset' was not declared in this scope
  memset(pre, -1, sizeof pre);
                            ^
0_0_18470823_6302.cpp: In function 'void build_map()':
0_0_18470823_6302.cpp:51:33: error: 'memset' was not declared in this scope
  memset(link, true, sizeof(link));
                                 ^