Compilare: user.cpp: In function ‘int main()’: user.cpp:66:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(sol.size() != 2 * n) { ~~~~~~~~~~~^~~~~~~~ user.cpp:77:29: warning: suggest parentheses around assignment used as truth value [-Wparentheses] vis[i] = per[i] = 0; ~~~~~~~^~~ user.cpp:35:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&t); ^ user.cpp:38:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&n); ^ user.cpp:41:39: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&x,&y); ^