Compilare: user.cpp: In function ‘int solve()’: user.cpp:117:42: 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:36:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &K); ^ user.cpp:38:27: 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:160:33: 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:161:35: 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:165:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &T); ^