Compilare: user.cpp: In function ‘long long int solveColor(int)’: user.cpp:88:59: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < nodes_for_color[current_col].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:103:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("kdist.in", "r", stdin); ^ user.cpp:104:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("kdist.out", "w", stdout); ^ user.cpp:107:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.cpp:110:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &xx, &yy); ^ user.cpp:115:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &col[i]); ^