next permuatation

class Solution {
    public void nextPermutation(int[] nums) {
        int k, l;

        for(k = nums.length-2; k>=0; k--) {
            if(nums[k] < nums[k+1]) {
                break;
            }
        }
        if(k < 0) {
            reverse(nums, 0);
        }else{
            for(l=nums.length-1; l>=0; l--) {
                if(nums[l] > nums[k]){
                    break;
                }
            }

            swap(nums, k,l);
            reverse(nums, k+1);
        }
    }

    public void swap(int[] nums, int l, int r){
        int temp = nums[l];
        nums[l]=nums[r];
        nums[r]= temp;
    }


    public void reverse(int[] nums, int from) {
        int j = nums.length-1;
        while(from < j) {
            swap(nums, from, j);
            from++;
            j--;
        }
    }
}