Finds all permutations of a list containing distinct integers.

ListOperations.java

public class ListOperations {
    public void nextPermutation(int[] nums) {
        int nonDecIdx=nums.length-1;
        //int[] result;
        if(nums.length==1)
            return;
        while(nonDecIdx > 0){
            if(nums[nonDecIdx] > nums[nonDecIdx-1])
                break;
            nonDecIdx--;
        }
        //System.out.println("nondec "+nonDecIdx+" nums,lght "+(nums.length-1) );
        if(nonDecIdx == 0){
            performSpReverse(nums,0,nums.length-1);
            return;
        }else{
            int swapW = nums[nonDecIdx-1];
            for(int i=nums.length-1; i >= nonDecIdx; i--){
                if(swapW < nums[i]){
                    performSpSwap(nums,nonDecIdx-1,i);
                    //Collections.swap(Arrays.asList(nums),nonDecIdx-1, i);
                    break;
                }
            }
            //Reverse the sub array
             performSpReverse(nums,nonDecIdx,nums.length-1);
            
        }
        return;
    }
    public void performSpReverse(int[] nums, int left, int right){
        
        while(left<=right){
            //Collections.swap(Arrays.asList(nums),left,right);
            performSpSwap(nums,left,right);
            left++;
            right--;
        }
    }
    public void performSpSwap(int[] nums, int left, int right){
        int temp;
        temp = nums[left];
        nums[left] = nums[right];
        nums[right] = temp;
    }
}