ro.cpp: In function 'void dfsbcx(int, int)': ro.cpp:19: warning: comparison between signed and unsigned integer expressions ro.cpp: In function 'void dfs(int, int)': ro.cpp:47: warning: comparison between signed and unsigned integer expressions ro.cpp:57: warning: comparison between signed and unsigned integer expressions ro.cpp:85: warning: comparison between signed and unsigned integer expressions ro.cpp:92: warning: comparison between signed and unsigned integer expressions ro.cpp:106: warning: comparison between signed and unsigned integer expressions ro.cpp: In function 'void undo(int, int, int)': ro.cpp:148: warning: comparison between signed and unsigned integer expressions ro.cpp:159: warning: comparison between signed and unsigned integer expressions ro.cpp:171: warning: comparison between signed and unsigned integer expressions ro.cpp: In function 'int main()': ro.cpp:215: warning: comparison between signed and unsigned integer expressions ro.cpp:193: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result ro.cpp:195: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result ro.cpp:198: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result