Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.

Each number in C may only be used once in the combination.

Note:
All numbers (including target) will be positive integers.
The solution set must not contain duplicate combinations.
For example, given candidate set[10, 1, 2, 7, 6, 1, 5] and target 8,
A solution set is:

[
  [1, 7],
  [1, 2, 5],
  [2, 6],
  [1, 1, 6]
]

題意：這題和上一題39題，簡直一模一樣，那道題是可以重復(fù)的應(yīng)用同一個(gè)位置的數(shù)字，這題是不允許重復(fù)的應(yīng)用同一個(gè)位置的數(shù)字。

只需要在上一題的基礎(chǔ)上，遞歸的時(shí)候每次都大1，即不能等于本身就可以了。

java代碼：

public List<List<Integer>> combinationSum2(int[] candidates, int target) {
        Arrays.sort(candidates);
        List<List<Integer>> result = new ArrayList<List<Integer>>();
        getResult(result, new ArrayList<Integer>(), candidates, target, 0);
        return result;
    }

    public void getResult(List<List<Integer>> result, List<Integer> current, int[] candiates, int target, int start) {
        if (target > 0) {
            for (int i = start; i < candiates.length && target >= candiates[i]; i++) {
                current.add(candiates[i]);
                getResult(result, current, candiates, target - candiates[i], i + 1);
                current.remove(current.size() - 1);
            }
        } else if (target == 0) {
            if (!result.contains(current)) {
                result.add(new ArrayList<Integer>(current));
            }
        }
    }