Compilare: main.cpp: In function 'void solve_and_write()': main.cpp:22:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = 0; k < G[j].size(); k++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void read_data()': main.cpp:33:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for(i = 1; i <= M; i++) ^~~ main.cpp:35:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' G[a].pb(b); ^