Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:18:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = prec; i < L[n].size(); i++){ ^ user.cpp: In function ‘void DFS(int, int)’: user.cpp:39:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < L[v].size(); i++){ ^ user.cpp: In function ‘int main()’: user.cpp:84:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v1.size() && x < 2; i++){ ^ user.cpp:127:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ^ user.cpp:134:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v.size() && ok == 0; j++){ ^ user.cpp:60:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciclu2.in","r",stdin); ^ user.cpp:61:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ciclu2.out","w",stdout); ^ user.cpp:123:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&k); ^