Compilare: user.cpp: In function ‘void tarjan()’: user.cpp:85:12: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(j!=i && a[i][j]) ^ user.cpp: In function ‘void dfs_dp(int)’: user.cpp:108:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<=lt[k].size();i++) d[0][i]=1; ^ user.cpp:112:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1;j<=lt[k].size();j++) ^ user.cpp: In function ‘void read()’: user.cpp:25:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&n,&m,&K); ^ user.cpp:28:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y); ^ user.cpp: In function ‘int main()’: user.cpp:153:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dep.in","r",stdin); ^ user.cpp:154:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dep.out","w",stdout); ^