LeetCode0039组合总和

题目描述

java代码

class Solution {
    public List<List<Integer>> combinationSum(int[] candidates, int target) {
        List<List<Integer>> res=new ArrayList<>();
        Arrays.sort(candidates);
        backtracking(res,new ArrayList<>(),candidates,target,0);
        return res;
    }
    public void backtracking(List<List<Integer>> res,List<Integer> tmp,int[] candidates,int target,int start){
        if(target==0){
            res.add(new ArrayList<>(tmp));
        }
        for(int i=start;i<candidates.length&&candidates[i]<=target;i++){
            tmp.add(candidates[i]);
            backtracking(res,tmp,candidates,target-candidates[i],i);
            tmp.remove(tmp.size()-1);
        }
    }
}