arb.cpp: In function 'void DFS(int, int)': arb.cpp:12: warning: unused variable 'i' arb.cpp: In function 'void Update(int, int)': arb.cpp:25: warning: statement has no effect arb.cpp: In function 'int Query(int)': arb.cpp:30: warning: statement has no effect arb.cpp: In function 'void read(int&)': arb.cpp:39: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result arb.cpp:47: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result arb.cpp: In function 'int main()': arb.cpp:55: warning: unused variable 'q' arb.cpp:53: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result arb.cpp:54: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result arb.cpp:56: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result