BEAKJOON JAVA ALGORITHM #1722(순열의 순서)

https://www.acmicpc.net/problem/1722

import java.util.Scanner; public class a1722_2 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int num = sc.nextInt(); int check = sc.nextInt(); long[] f = new long[num+1]; boolean[] c = new boolean[num+1]; f[0] = 1; for(int i=1; i<=num; i++) { f[i] = f[i-1]*i; } if(check == 1) {//num까지 순열중 where번째 순열은? long where = sc.nextLong(); int[] arr = new int[num]; for(int i=0 ; i<num ; i++) { for(int j=1; j<=num; j++) { if(c[j] == true) continue; if(f[num-i-1] < where) { where -= f[num-i-1]; }else { arr[i] = j; c[j] = true; break; } } } for(int i=0; i<num; i++) { System.out.print(arr[i]+" "); } }else {//주어진순열이 몇번째순열? int[] arr = new int[num]; for(int i=0; i<num; i++) { arr[i] = sc.nextInt(); } long result = 0; for(int i=0; i<num; i++) { for(int j=1; j<arr[i]; j++) { if(c[j] == false) { result += f[num-i-1]; } } c[arr[i]] = true; } System.out.println(result+1); } } }