Compilare: user.cpp: In function ‘bool search_value(int, int)’: user.cpp:35:9: warning: unused variable ‘L’ [-Wunused-variable] int L = val % MOD; ^ user.cpp: In function ‘int solve()’: user.cpp:70:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < A[k].size(); ++j) { ^ user.cpp: In function ‘void read()’: user.cpp:23:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &K); ^ user.cpp:25:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^ user.cpp: In function ‘int main()’: user.cpp:102:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nk.in", "r", stdin); ^ user.cpp:103:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nk.out", "w", stdout); ^ user.cpp:106:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &T); ^