Compilare: user.cpp: In function ‘void solve_easy()’: user.cpp:59:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int kk = 0; kk < Q[i].size(); kk++) { ^ user.cpp: In function ‘void dfs_up(int)’: user.cpp:102:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < list[node].size(); i++) { ^ user.cpp:131:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < list[node].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:189:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hacker2.in","r",stdin); ^ user.cpp:190:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hacker2.out","w",stdout); ^ user.cpp:192:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:194:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &d); ^ user.cpp:200:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &d); ^