Compilare: user.cpp: In member function ‘void aint::combine(std::vector<std::pair<int, int> >&, std::vector<std::pair<int, int> >&, std::vector<std::pair<int, int> >&)’: user.cpp:32:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < dest.size(); i = j) { ^ user.cpp:35:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = i; j < dest.size(); j++) { ^ user.cpp: In function ‘int main()’: user.cpp:140:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j < work.nodes.size(); j++) { ^ user.cpp:115:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("color4.in","r",stdin); ^ user.cpp:116:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("color4.out","w",stdout); ^ user.cpp:118:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &c); ^ user.cpp:120:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ user.cpp:130:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &op, &x); ^ user.cpp:133:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &c); ^