Compilare: user.cpp: In function ‘void compute(int)’: user.cpp:20:10: warning: statement has no effect [-Wunused-value] for(i;i<=20;i++) ^ user.cpp: In function ‘void downDFS(int, int)’: user.cpp:33:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<g[node].size();i++) ^ user.cpp: In function ‘void upDFS(int, int)’: user.cpp:52:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<g[node].size();i++) ^ user.cpp:68:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<g[node].size();i++) ^ user.cpp: In function ‘void dadDFS(int, int)’: user.cpp:87:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<g[node].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:122:19: warning: variable ‘z’ set but not used [-Wunused-but-set-variable] int n,m,i,x,y,z,c,p,q,sum,node; ^ user.cpp:120:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hacker2.in","r",stdin); ^ user.cpp:121:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hacker2.out","w",stdout); ^ user.cpp:123:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:125:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&c); ^ user.cpp:138:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&p); ^ user.cpp: In function ‘void upDFS(int, int)’: user.cpp:73:60: warning: ‘node2’ may be used uninitialized in this function [-Wmaybe-uninitialized] upNode[g[node][i].first]=downNode[node2]; ^ user.cpp:79:60: warning: ‘node1’ may be used uninitialized in this function [-Wmaybe-uninitialized] upNode[g[node][i].first]=downNode[node1]; ^