Compilare: user.cpp: In function ‘void solve()’: user.cpp:45:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<tr[i].size()-1;j++) ^ user.cpp: In function ‘int main()’: user.cpp:69:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<w[x].size()&&ok;j++) ^ user.cpp:53:16: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(iN); ^ user.cpp:54:17: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(ouT); ^ user.cpp:55:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:57:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^