Compilare: user.cpp: In function ‘void reduction()’: user.cpp:46:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(; i < E.size(); ++ i){ ^ user.cpp: In function ‘void solve()’: user.cpp:69:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < E.size()){ ^ user.cpp: In function ‘void read()’: user.cpp:27:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &L); ^ user.cpp:29:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &p[i]); ^ user.cpp:31:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &R[i].x, &R[i].y); ^