Compilare: main.cpp: In function 'void dfs(long long int, long long int)': main.cpp:14:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<val.size();i++) ~^~~~~~~~~~~ main.cpp:22:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<val.size();i++) ~^~~~~~~~~~~ main.cpp: In function 'void dfs2(long long int, long long int)': main.cpp:28:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<val.size();i++) ~^~~~~~~~~~~ main.cpp: In function 'long long int calc(long long int)': main.cpp:35:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<val.size();i++) ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:61:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("palatulvoltaic.in","r",stdin); ^ main.cpp:62:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("palatulvoltaic.out","w",stdout); ^ main.cpp:63:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&n,&k); ^ main.cpp:67:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld",&v[i]); ^ main.cpp:83:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^