algebra.cpp: In function 'void DFS(int, int)': algebra.cpp:21: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x algebra.cpp:21: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x algebra.cpp:23: warning: comparison between signed and unsigned integer expressions algebra.cpp: In function 'void build(int, int, int)': algebra.cpp:41: warning: comparison between signed and unsigned integer expressions