这是一种实现方法：
public static void permutation(List<coordinate> nums) { List<List<coordinate>> accum = new ArrayList<List<coordinate>>(); permutation(accum, Arrays.<coordinate>asList(), nums); System.out.println(accum);}private static void permutation(List<List<coordinate>> accum, List<coordinate> prefix, List<coordinate> nums) { int n = nums.size(); if (n == 0) { accum.add(prefix); } else { for (int i = 0; i < n; ++i) { List<coordinate> newPrefix = new ArrayList<coordinate>(); newPrefix.addAll(prefix); newPrefix.add(nums.get(i)); List<coordinate> numsLeft = new ArrayList<coordinate>(); numsLeft.addAll(nums); numsLeft.remove(i); permutation(accum, newPrefix, numsLeft); } }}
