Compilare: user.cpp: In function ‘int cost(int, int)’: user.cpp:28:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:68:23: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(IN, stdin); ^ user.cpp:69:25: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(OUT, stdout); ^ user.cpp:70:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:73:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &c); ^ user.cpp: In function ‘void Dijkstra(int)’: user.cpp:35:14: warning: ‘ck’ may be used uninitialized in this function [-Wmaybe-uninitialized] int k=1, ck; ^