mere.cpp: In function 'void dfs(int)': mere.cpp:32: warning: comparison between signed and unsigned integer expressions mere.cpp: In function 'int main()': mere.cpp:45: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x mere.cpp:45: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x mere.cpp:49: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x mere.cpp:49: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x mere.cpp:53: warning: comparison between signed and unsigned integer expressions