Compilare: main.cpp: In function 'int main()': main.cpp:85:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("23.in", "r", stdin); ^ main.cpp:86:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("23.out", "w", stdout); ^ main.cpp:89:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:101:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &nr); ^ main.cpp: In function 'int cb(int)': main.cpp:80:12: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized] return ans; ^~~