Compilare: user.cpp: In function ‘int read()’: user.cpp:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=n;i++) ^ user.cpp: In function ‘int solve()’: user.cpp:51:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(index < n) ^ user.cpp: In function ‘int write()’: user.cpp:84:21: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int64_t {aka long long int}’ [-Wformat=] printf("%d", sum); ^ user.cpp: In function ‘int read()’: user.cpp:32:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN,"r",stdin); ^ user.cpp:33:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT,"w",stdout); ^ user.cpp:34:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ", &n, &k); ^ user.cpp:38:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &arr[i]); ^