package LeetCode;

import java.util.ArrayList;

import java.util.List;

public class Permutations {

List<List<Integer>> lists;

int count=0;

public List<List<Integer>> permute(int[] nums,int k) {

lists = new ArrayList<List<Integer>>();

helper(nums, 0, nums.length, new ArrayList<Integer>(),k);

return lists;

}

private void helper(int[] nums, int start, int length, List<Integer> list,int k) {

if (list.size() == length) {

lists.add(new ArrayList<Integer>(list));

count++;

return;

}

if (start >= length || count>k) {

return;

}

for (int i = 0; i < length; i++) {

if (list.contains(nums[i])) {

continue;

}

// Choose

list.add(nums[i]);

// Explore

helper(nums, i, length, new ArrayList<Integer>(list),k);

// UnChoose

list.remove(list.size() - 1);

}

}

public static void main(String[]args){

Permutations permutations=new Permutations();

int[] nums={1,2,3,4};

System.out.println(permutations.permute(nums,3));

}

}