Compilare: user.cpp: In function ‘void dfs2(int, int)’: user.cpp:79:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int mask = 1; mask < dp[x].size(); mask ++ ) { ^ user.cpp:87:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < lst[x].size(); i ++ ) { ^ user.cpp:93:50: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int mask = 1; mask < dp[x].size(); mask ++ ) { ^ user.cpp:103:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < lst[x].size(); i ++ ) { ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:16:38: 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, 4096, fin); ^