题解 | 有重复项数字的全排列

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param num int整型一维数组
     * @return int整型ArrayList<ArrayList<>>
     */
    public ArrayList<ArrayList<Integer>> permuteUnique (int[] num) {
        // write code here
        Arrays.sort(num);
        
        ArrayList<ArrayList<Integer>> result = new ArrayList<ArrayList<Integer>>();
        ArrayList<Integer> list = new ArrayList<Integer>();
        ArrayList<Integer> pos = new ArrayList<Integer>();
        diGui(num, result, list,pos);
        return result;

    }

    public void diGui(int[] num, ArrayList<ArrayList<Integer>> result,
                      ArrayList<Integer> list,ArrayList<Integer> pos) {

        if (list.size() == num.length) {
            if (!result.contains(list)) {
                result.add(new ArrayList<Integer>(list));
            }
        }
        for (int i = 0; i < num.length; i++) {
            if (pos.contains(i)) continue;
            
            pos.add(i);
            list.add(num[i]);
            diGui(num, result, list,pos);
            list.remove(list.size() - 1);
            pos.remove(pos.size()-1);
        }
    }
}