Compilare: user.cpp: In function ‘int main()’: user.cpp:64:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(sol.size()<k) printf("-1"); ^ user.cpp:65:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else for(int i=0;i<sol.size();i++) printf("%d %d\n",sol[i].first,sol[i].second); ^ user.cpp:27:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("romania.in", "r", stdin); ^ user.cpp:28:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("romania.out", "w", stdout); ^ user.cpp:30:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^ user.cpp:33:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^