LeetCode047全排列II

题目:

给定一个可包含重复数字的序列 nums ，按任意顺序 返回所有不重复的全排列。

示例 1：

• 输入：nums = [1,1,2]
• 输出：
  [[1,1,2],
  [1,2,1],
  [2,1,1]]

示例 2：

• 输入：nums = [1,2,3]
• 输出：[[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]

提示：

• 1 <= nums.length <= 8
• -10 <= nums[i] <= 10

java:

public class Leetcode047 {

    public static List<List<Integer>> res = new ArrayList<>();

    public static List<Integer> path = new ArrayList<>();

    public static List<List<Integer>> permute(int[] nums) {
        boolean[] used = new boolean[nums.length];
        Arrays.fill(used, false);
        Arrays.sort(nums);        
        backtrack(nums, used);
        return res;
    }

    private static void backtrack(int[] nums, boolean[] used) {
        if (path.size() == nums.length) {
            res.add(new ArrayList<>(path));
            return;
        }

        for (int i = 0; i < nums.length; i++) {
            if (i > 0 && nums[i] == nums[i - 1] && used[i - 1] == false) {
                continue;
            }

            if (used[i] == false) {
                used[i] = true;
                path.add(nums[i]);
                backtrack(nums, used);
                path.remove(path.size() - 1);
                used[i] = false;
            }
        }
    }

    public static void main(String[] args) {
        int[] nums = {1, 2, 3};
        System.out.println(permute(nums));
    }
}

Go:

package LeetCode

import "sort"

var (
	res047  [][]int
	path047 []int
	st047   []bool
)

func PermuteUnique047(nums []int) [][]int {
	res047 = make([][]int, 0)
	path047 = make([]int, len(nums))
	st047 = make([]bool, len(nums))
	sort.Ints(nums)
	dfs047(nums, 0)
	return res047
}

func dfs047(nums []int, index int) {
	if index == len(nums) {
		tmp := make([]int, len(nums))
		copy(tmp, nums)
		res047 = append(res047, tmp)
	}

	for i := 0; i < len(nums); i++ {
		if i != 0 && nums[i] == nums[i-1] && !st047[i-1] {
			continue
		}
		if !st047[i] {
			path047 = append(path047, nums[i])
			st047[i] = true
			dfs047(nums, index+1)
			st047[i] = false
			path047 = path047[:len(path047)-1]
		}
	}
}


func main() {
	nums := []int{1, 1, 2}
	path := LeetCode.PermuteUnique047(nums)
	fmt.Println(path)
}

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