Compilare: user.cpp: In function ‘int main()’: user.cpp:143:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(pos[j] < Q[j].size() && dp[1][j] <= Q[j][pos[j]].lg) ^ user.cpp:176:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(pos[j] < Q[j].size() && dp[i][j] <= Q[j][pos[j]].lg) ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:46:39: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, BSIZE, fin); ^