Compilare: user.cpp: In function ‘int solve(std::vector<std::pair<int, int> >&, std::vector<std::pair<int, int> >&)’: user.cpp:47:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (p1 < v1.size() || p2 < v2.size()) { ^ user.cpp:47:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (p1 < v1.size() || p2 < v2.size()) { ^ user.cpp:50:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p1 == v1.size()) ^ user.cpp:52:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if (p2 == v2.size()) ^ user.cpp: In function ‘int main()’: user.cpp:81:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("carpetbomber.in","r",stdin); ^ user.cpp:82:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("carpetbomber.out","w",stdout); ^ user.cpp:84:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:86:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &t, &x, &y); ^