hdu 1027 Ignatius and the Princess II（正、逆康托）

int const MAXM=10000;


int fac[15];
int ans[1005];
int kk;
int n,m;
vector<int> pq;


int main(){

    int cn=0;
    fac[0]=1;
    while(1){
        ++cn;
        fac[cn]=fac[cn-1]*cn;
        if(fac[cn]>MAXM){
            --cn;
            break;
        }
    }

    while(cin>>n>>m){

        pq.clear();
        rep(i,1,n) pq.push_back(i);

        int a;
        kk=0;
        --m;

        rep2(i,n-1,0){
            if(i>cn){
                a=0;
                ans[++kk]=pq.at(a);
                pq.erase(pq.begin()+a,pq.begin()+a+1);
            }else{
                a=m/fac[i];
                m%=fac[i];
                ans[++kk]=pq.at(a);
                pq.erase(pq.begin()+a,pq.begin()+a+1);
            }
        }

        printf("%d",ans[1]);
        rep(i,2,kk) printf(" %d",ans[i]); cout<<endl;
    }

    return 0;
}