foo.cc: In function 'void Output(std::vector<std::vector<int> >)':
foo.cc:23:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |  for(int i = 1;i<maze.size();i++)
      |                ~^~~~~~~~~~~~
foo.cc:25:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |   for(int j = 1;j<maze[0].size();j++)
      |                 ~^~~~~~~~~~~~~~~
foo.cc: In function 'void DFS(std::vector<std::vector<int> >&, pos, pos, pos, int, int, ll&)':
foo.cc:55:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |   if(nownext.x>maze[0].size()-1 ||nownext.x<1) continue; //走出迷宫
      |      ~~~~~~~~~^~~~~~~~~~~~~~~~~
foo.cc:56:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   if(nownext.y>maze.size()-1 ||nownext.y<1) continue; //走出迷宫
      |      ~~~~~~~~~^~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:69:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   69 |  freopen("in.txt","r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~

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