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| import java.util.*;
import java.io.*;
public class Main{
static List<List<Integer>> res = new ArrayList<>();
static Set<Integer> set = new HashSet<>();
static BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
public static void main(String[] args) throws Exception{
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int m = n;
dfs(1, n, m, new ArrayList<>());
for(List<Integer> list : res){
for(int i = 0; i < list.size(); i++){
log.write(String.valueOf(list.get(i)));
if(i != list.size()-1){
log.write(" ");
}
}
log.write("\n");
}
log.flush();
}
public static void dfs(int cur, int n, int m, List<Integer> ans){
if(ans.size() == m){
res.add(new ArrayList<>(ans));
return;
}
for(int i = cur; i <= n; i++){
if(set.contains(i)){
continue;
}
ans.add(i);
set.add(i);
dfs(cur, n, m, ans);
ans.remove(ans.size()-1);
set.remove(i);
}
}
}
|
