Compilare: main.cpp: In function 'int dijkstra()': main.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0 ; i < G[u].size() ; i ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:110:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("renovare.in" , "r" , stdin); ^ main.cpp:111:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("renovare.out" , "w" , stdout); ^ main.cpp:113:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld%lld" , &n , &m , &l); ^ main.cpp:116:54: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld%lld%lld" , &x , &y , &c , &z); ^