081 : 순열의 순서 구하기

 

 

 

 

 

팩토리얼

 

 

 

 

 

 

 

 

 

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) throws IOException {

        // ISC
        BufferedReader br =  new BufferedReader(new InputStreamReader(System.in));
        int V = Integer.parseInt(br.readLine());
        StringTokenizer st = new StringTokenizer(br.readLine());
        int signal = Integer.parseInt(st.nextToken());

        // D2F
        int[] TP = new int[21];
        int[] S = new int[21];
        boolean[] visited = new boolean[21];
        TP[0] = 1;
        for (int i = 1; i <= V; i++) {
            TP[i] = TP[i-1]*i;
        }

        // OEC + OP
        if (signal == 1) {
            int order = Integer.parseInt(st.nextToken());
            for (int i = 1; i <= V; i++) {
                for (int j = 1, counter = 1; j <= V; j++) {
                    if (visited[j])
                        continue;
                    if (order <= counter * TP[V-i]) {
                        order -= ((counter-1) * (TP[V-i]));
                        S[i] = j;
                        visited[j] = true;
                        break;
                    }
                    counter++;
                }
            }
            for (int i = 1; i <= V; i++) {
                System.out.print(S[i] + " ");
            }
        } else {
            int order = 1;
            for (int i = 1; i <= V; i++) {
                S[i] = Integer.parseInt(st.nextToken());
                int counter = 0;
                for (int j = 1; j < S[i]; j++) {
                    if (!visited[j])
                        counter++;
                }
                order += counter * TP[V-i];
                visited[S[i]] = true;
            }
            System.out.println(order);

        }
    }
}