Compilare: main.c: In function 'main': main.c:9:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("shop.in","r",stdin),freopen("shop.out","w",stdout),scanf("%lld%lld%lld",&n,&c,&l); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:9:34: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("shop.in","r",stdin),freopen("shop.out","w",stdout),scanf("%lld%lld%lld",&n,&c,&l); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:9:65: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("shop.in","r",stdin),freopen("shop.out","w",stdout),scanf("%lld%lld%lld",&n,&c,&l); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:11:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",a+i,b+i); ^~~~~~~~~~~~~~~~~~~~~~~~~