Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:18:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < A[x].size(); ++i) ^ user.cpp: In function ‘void DFS2(int)’: user.cpp:31:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < B[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:66:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < sol[i].size(); ++j) fprintf(fout,"%d ",sol[i][j]); ^ user.cpp:45:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d",&N,&M); ^ user.cpp:48:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d",&x,&y); ^