Compilare: user.cpp: In function ‘void solve()’: user.cpp:60:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<A[u].size(); ++i) ^ user.cpp:66:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<A[u].size(); ++i) { ^ user.cpp:78:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<sol.size(); ++i) ^ user.cpp: In function ‘void read()’: user.cpp:28:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &x); ^ user.cpp:31:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^ user.cpp:35:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^ user.cpp: In function ‘int main()’: user.cpp:85:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(INFL, "r", stdin); ^ user.cpp:86:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(OUTFL, "w", stdout); ^