Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:32:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[node].size(); ++i) ^ user.cpp: In function ‘void chains(int)’: user.cpp:48:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[node].size(); ++i) ^ user.cpp:58:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[node].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:150:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavypath.in","r",stdin); ^ user.cpp:151:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavypath.out","w",stdout); ^ user.cpp:153:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:155:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", v + i); ^ user.cpp:160:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp:177:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &op); ^ user.cpp:178:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^