TODO: 46. 全排列🔖递归

• https://leetcode-cn.com/problems/permutations/

• https://leetcode-cn.com/problems/permutations-ii/

  问题描述

  给定n个有序元素的集合，列出其可能出现的排列。

  问题思路

  代码思路

• 利用动态数组数据结构

  代码实现

  ```java package com.wztlink1013.al.递归法; import java.util.ArrayList;

/**

• 全排列问题
• */

public class Permuting { static ArrayList x = new ArrayList(); static int N; static int cnt = 0; static int t;

public static void main(String args[]) {
    int n = 10;
    Times.test("当n = " + n + "时候的耗费时间", new Times.Task() {
        public void execute() {
            PermutingCaller(n);
        }
    });
}
private static void PermutingCaller(int n) {
    N = n;
    for (int i = 0; i < n; ++i)
        x.add(i + 1);
    Permuting(0);
}
private static void Permuting(int i) {
    if (i < N - 1) {
        for (int j = i; j < N; j++) {
            t = x.get(i);
            x.set(i, x.get(j));
            x.set(j, t);
            Permuting(i + 1);
            t = x.get(i);
            x.set(i, x.get(j));
            x.set(j, t);
        }
    }
    else
        OutputOnePermutation();
}
private static void OutputOnePermutation()
{
    System.out.print(++cnt + " : ");
    for (int x : x)
        System.out.print(x + " ");
    System.out.println();
}

} ```

n:10

n