Compilare: main.cpp: In function 'long long int calc_vmax(int, int)': main.cpp:40:13: warning: unused variable 'ret' [-Wunused-variable] long long ret = 0; ^~~ main.cpp: In function 'int main()': main.cpp:58:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("halftree.in", "r", stdin); ^ main.cpp:59:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("halftree.out", "w", stdout); ^ main.cpp:61:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:64:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ main.cpp:71:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &c); ^