Compilare: user.cpp: In function ‘void Back2(int, int, int)’: user.cpp:64:9: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(Valid2(k,s,n)) ^ user.cpp: In function ‘int main()’: user.cpp:89:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("cumpanit.in", "r", stdin); ^ user.cpp:90:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("cumpanit.out", "w", stdout); ^ user.cpp:91:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%lld%lld", &a, &b); ^