foo.cpp: In function 'void bfs()':
foo.cpp:20:32: error: 'memset' was not declared in this scope
  memset(dis, false, sizeof(dis));
                                ^
foo.cpp: In function 'void SPFA()':
foo.cpp:44:31: error: 'memset' was not declared in this scope
  memset(dis, 0xff, sizeof(dis));
                               ^
foo.cpp: In function 'int main()':
foo.cpp:101:31: error: 'memset' was not declared in this scope
  memset(can, true, sizeof(can));
                               ^