"Leetcode-Interview algorithm classic-java Implementation" "046-permutations (Order)" __ Code

"046-permutations (order)" " leetcode-interview algorithm classic-java Implementation" "All topic Directory Index" Original title

Given A collection of numbers, return all possible permutations.
For example,
[1,2,3] have the following permutations:
[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].
The main effect of the topic

Given an array, returns all of his permutations.
ideas for solving problems

Solved by using the method of divide and conquer.
Code Implementation

Algorithm implementation class

Import java.util.*;

public class Solution {
    private list<list<integer>> result;
    Public list<list<integer>> permute (int[] num) {result

        = new linkedlist<> ();
        if (num!= null) {
            permute (0, num);
        }

        return result;
    }

    private void Permute (int i, int[] num) {

        if (i = = num.length) {
            list<integer> L = new arraylist<> (); for
            (int n:num) {
                l.add (n);
            }

            Result.add (l);
        } else {for

            (int j = i; J < Num.length; J + +) {
                swap (num, j, i);
                Permute (i + 1, num);
                Swap (num, j, i);

    }} private void Swap (int[] A, int x, int y) {
        int tmp = a[x];
        A[X] = A[y];
        A[y] = tmp;
    }
}

Evaluation Results

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