Compilare: user.cpp: In function ‘void add(int, int)’: user.cpp:13:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < h[l][r].size(); ++i) ^ user.cpp: In function ‘int Search(int)’: user.cpp:29:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < h[1][r].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:59:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < h[0][i].size(); ++j) ^ user.cpp:35:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.in","r",stdin); ^ user.cpp:36:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("eqs.out","w",stdout); ^ user.cpp:45:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d",&a,&b,&c,&d,&e); ^