Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:19:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g2[k].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:53:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g1[x].size(); i++) ^ user.cpp:70:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int assa=0;assa<topo.size();assa++) ^ user.cpp:75:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g2[x].size(); i++) ^ user.cpp:28:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pm2.in","r",stdin); ^ user.cpp:29:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pm2.out","w",stdout); ^ user.cpp:31:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:33:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&cost[i]); ^ user.cpp:37:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^ user.cpp:40:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&y); ^