Compilare: main.cpp: In function 'void dijkstra(int)': main.cpp:72:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[1].size();i++) ~^~~~~~~~~~~~ main.cpp:81:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] {for(i=0;i<a[x].size();i++) ~^~~~~~~~~~~~ main.cpp:64:8: warning: unused variable 'val' [-Wunused-variable] {int i,val,now; ^~~ main.cpp:64:12: warning: unused variable 'now' [-Wunused-variable] {int i,val,now; ^~~