Compilare: user.cpp: In function ‘void solve()’: user.cpp:25:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < G[x].size(); i++) { ^ user.cpp:16:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, k, val, x; ^ user.cpp:16:15: warning: unused variable ‘k’ [-Wunused-variable] int i, j, k, val, x; ^ user.cpp:16:18: warning: variable ‘val’ set but not used [-Wunused-but-set-variable] int i, j, k, val, x; ^ user.cpp: In function ‘int main()’: user.cpp:35:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.in", "r", stdin); ^ user.cpp:36:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.out", "w", stdout); ^ user.cpp:40:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:43:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &a, &b, &c); ^