Compilare: user.cpp: In function 'void insert_to_used(edge)': user.cpp:21: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'bool reduce()': user.cpp:62: warning: comparison between signed and unsigned integer expressions user.cpp:81: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'bool check_reduce(std::vector<edge, std::allocator<edge> >, int)': user.cpp:94: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void reduce_more(int)': user.cpp:103: warning: comparison between signed and unsigned integer expressions user.cpp:110: warning: comparison between signed and unsigned integer expressions user.cpp:115: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int main()': user.cpp:140: warning: comparison between signed and unsigned integer expressions user.cpp:141: warning: too many arguments for format