judete.cpp: In function 'void dfs(int, int)': judete.cpp:16: warning: comparison between signed and unsigned integer expressions judete.cpp: In function 'int main()': judete.cpp:46: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result judete.cpp:48: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result