Compilare: main.cpp: In function 'void solve()': main.cpp:29:16: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[1000002]' [-Wformat=] scanf("%s", &s); ^ main.cpp:33:26: warning: NULL used in arithmetic [-Wpointer-arith] for (int i = 0; s[i] != NULL; ++i) ^~~~ main.cpp:29:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s", &s); ^ main.cpp: In function 'int main()': main.cpp:72:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("prefix.in", "r", stdin); ^ main.cpp:73:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("prefix.out", "w", stdout); ^ main.cpp:76:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^