Compilare: user.cpp: In function ‘unsigned int get_int()’: user.cpp:12:13: warning: suggest parentheses around comparison in operand of ‘|’ [-Wparentheses] for(; c < 48 | c > 57; c = getchar()); ~~^~~~ user.cpp:14:13: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] for(; c > 47 & c < 58; nr = nr * 10 + c - 48, c = getchar()); ~~^~~~ user.cpp: In function ‘int main()’: user.cpp:90:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i = 0; i < M; ++i) ~~^~~ user.cpp:99:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i = 1; i <= N; ++i) ~~^~~~ user.cpp:114:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i = 0; i < M; ++i) ~~^~~ user.cpp:125:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i = 1; i <= N; ++i) ~~^~~~ user.cpp: At global scope: user.cpp:48:37: warning: always_inline function might not be inlinable [-Wattributes] __attribute__((always_inline)) void put_int(unsigned int x) ^~~~~~~ user.cpp: In function ‘int main()’: user.cpp:79:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.in", "r", stdin); ^ user.cpp:80:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.out", "w", stdout); ^ user.cpp:106:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.in", "r", stdin); ^