[Java] Java全排列算法字典序下的下一个排列讲解

public void reverse(int []nums,int l,int r){
  while(l<r){
    int tmp=nums[l];
    nums[l]=nums[r];
    nums[r]=tmp;
    l++;
    r--;
  }
  }
  public void nextpermutation(int[] nums) {
  if(nums.length==0||nums.length==1) return;
  int i=nums.length-1;
  for(;i>=1;i--){
    if(nums[i]>nums[i-1])
    break;
  }
  if(i==0){
    arrays.sort(nums);
    return;
  }
  int index=i-1;
  int diff=nums[i-1];
  for(i=nums.length-1;i>=0;i--){
    if(nums[i]>diff)
    break;
  }
  int tmp=nums[index];
  nums[index]=nums[i];
  nums[i]=tmp;
  reverse(nums,index+1,nums.length-1);
  }