class Solution {    public void nextPermutation(int[] nums) {        int i=nums.length-1;        while(i>0&&nums[i-1]>=nums[i])i--;        if(i==0)        {            Arrays.sort(nums);            return;                    }        int j=i-1;        i=nums.length-1;        while(nums[j]>=nums[i])i--;        swap(j, i, nums);                i=nums.length-1;        j++;        while(j