Compilare: main.cpp: In function 'void bfsX()': main.cpp:40:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < a[x].size(); i++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void solve()': main.cpp:54:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < dist[i].size(); j++) { ~~^~~~~~~~~~~~~~~~ main.cpp:59:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k < a[dist[i][j]].size(); k++) ~~^~~~~~~~~~~~~~~~~~~~~~