Compilare: user.cpp: In function ‘void solve()’: user.cpp:36:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[x].size(); i++) ^ user.cpp:27:9: warning: unused variable ‘j’ [-Wunused-variable] int i, j, k, val, x; ^ user.cpp:27:12: warning: unused variable ‘k’ [-Wunused-variable] int i, j, k, val, x; ^ user.cpp: In function ‘int main()’: user.cpp:44:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.in", "rt", stdin); ^ user.cpp:45:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.out", "wt", stdout); ^ user.cpp:49:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ user.cpp:52:58: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d\n", &a, &b, &c), G[a].pb(b), C[a].pb(c); ^