Compilare: user.cpp: In function ‘int bfs(int, int)’: user.cpp:31:7: warning: unused variable ‘last’ [-Wunused-variable] int last = 1; ^ user.cpp: In function ‘int main()’: user.cpp:50:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sahara.in", "r", stdin); ^ user.cpp:51:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sahara.out", "w", stdout); ^ user.cpp:52:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &N, &M, &Q); ^ user.cpp:58:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(scanf("%d", &T); T; -- T) { ^ user.cpp:60:54: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &x1, &y1, &x2, &y2, &val); ^