Compilare: main.c: In function 'preprocess': main.c:81:9: warning: unused variable 'i' [-Wunused-variable] int i; ^ main.c: In function 'main': main.c:129:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("lca.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:130:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("lca.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:132:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &q); ^~~~~~~~~~~~~~~~~~~~~ main.c:137:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &f); ^~~~~~~~~~~~~~~ main.c:148:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^~~~~~~~~~~~~~~~~~~~~