package LeetCode;

import java.util.*;

public class LC_40 {
    static List<List<Integer>> res = new ArrayList<>();
    static ArrayList<Integer> path = new ArrayList<>();

    public static void main(String[] args) {
        int[] candidates = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1};
        int target = 27;
        combinationSum2(candidates, target);
    }

    public static List<List<Integer>> combinationSum2(int[] candidates, int target) {
        List<List<Integer>> resList = new ArrayList<>();
        if (candidates == null || candidates.length == 0) return resList;
        Arrays.sort(candidates);
        backtracking(candidates, target, 0);
        System.out.println(res);
        return res;
    }

    public static void backtracking(int[] candidates, int target, int startIndex) {
        if (path.stream().mapToInt(Integer::intValue).sum() == target) {
            res.add(new ArrayList<>(path));
            return;
        }
        if (path.stream().mapToInt(Integer::intValue).sum() > target) return;
        for (int i = startIndex; i < candidates.length; i++) {
            if (i > startIndex && candidates[i] == candidates[i - 1]) continue;
            path.add(candidates[i]);
            backtracking(candidates, target, i + 1);
            path.remove(path.size() - 1);
        }
    }
}