Compilare: user.cpp: In function ‘bool compare(int, int, int, int)’: user.cpp:45:9: warning: unused variable ‘hash2’ [-Wunused-variable] int hash2 = (h2[b] - (1LL * h2[a - 1] * b2[dif1]) % mod2 + mod2) % mod2; ^ user.cpp:48:9: warning: unused variable ‘hash4’ [-Wunused-variable] int hash4 = (h4[d] - (1LL * h4[c - 1] * b2[dif2]) % mod2 + mod2) % mod2; ^ user.cpp: In function ‘int main()’: user.cpp:56:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("partialmatch.in", "r", stdin); ^ user.cpp:57:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("partialmatch.out", "w", stdout); ^ user.cpp:59:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", a + 1); ^ user.cpp:60:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", b + 1); ^ user.cpp:65:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &K); ^