Compilare: main.cpp: In function 'int bfs(int, int)': main.cpp:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g[u].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:31:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] { freopen("sate.in", "r", stdin); ^ main.cpp:32:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sate.out", "w", stdout); ^ main.cpp:34:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &x, &y); ^ main.cpp:36:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x1, &y1, &z); ^