Compilare: user.cpp: In function ‘long long int solve()’: user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < p.size(); ++ i) ^ user.cpp:21:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < p.size() && p[i].first == p[j].first) j ++; ^ user.cpp: In function ‘int main()’: user.cpp:58:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("metrou4.in", "r", stdin); ^ user.cpp:59:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("metrou4.out", "w", stdout); ^ user.cpp:61:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &t); ^ user.cpp:66:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &n); ^ user.cpp:69:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &x[i], &y[i]); ^