Compilare: user.cpp: In function ‘int main()’: user.cpp:42:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size() != n-1) return printf("-1\n"),0; ^ user.cpp: In function ‘std::pair<int, int> go(std::pair<int, int>, std::pair<int, int>)’: user.cpp:14:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:17:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("permsplit.in","r",stdin); ^ user.cpp:18:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("permsplit.out","w",stdout); ^ user.cpp:23:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:25:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",s+i); ^