foo.cpp: In function 'int augmentint_path()':
foo.cpp:40:29: error: 'memset' was not declared in this scope
  memset(left,-1,sizeof(left));
                             ^
foo.cpp: In function 'int main()':
foo.cpp:62:29: error: 'memset' was not declared in this scope
  memset(head,-1,sizeof(head));
                             ^