Compilare: user.cpp: In function ‘int main()’: user.cpp:83:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<m.size(); ++j) ^ user.cpp:93:30: warning: format ‘%lf’ expects argument of type ‘double’, but argument 2 has type ‘int’ [-Wformat=] printf("%.6lf\n",cost); ^ user.cpp:95:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<sol.size(); j++) ^ user.cpp:67:9: warning: unused variable ‘k’ [-Wunused-variable] int k=0; ^ user.cpp: In function ‘bool unionset(int, int)’: user.cpp:52:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:63:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("desen.in","r",stdin); ^ user.cpp:64:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("desen.out","w",stdout); ^ user.cpp:66:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&n); ^ user.cpp:68:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a[1].x,&a[1].y); ^ user.cpp:73:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a[i].x,&a[i].y); ^