146.组合总和

class Solution {
    List<List<Integer>> res=new ArrayList<>();
    List<Integer> li=new ArrayList<>();
    public List<List<Integer>> combinationSum(int[] candidates, int target) {
        solut(candidates,target,0,0);
        return res;
    }
    void solut(int[] candidates, int target,int index,int listSum){
        if(listSum==target){
            res.add(new ArrayList<>(li));
            return;
        }
        for(int i=index;i<candidates.length&&listSum<=target;i++){
            li.add(candidates[i]);
            listSum+=candidates[i];
            solut(candidates,target,i,listSum);
            listSum-=li.get(li.size()-1);
            li.remove(li.size()-1);
        }
    }
}

class Solution(object):
    def combinationSum(self, candidates, target):
        res=[]
        li=[]
        def solut(candidates,target,index,listSum):
            if listSum>target:
                return
            if listSum==target:
                res.append(li[:])
                return
            for i in range(index,len(candidates)):
                li.append(candidates[i])
                listSum+=candidates[i]
                solut(candidates,target,i,listSum)
                listSum-=li.pop()
        solut(candidates,target,0,0)
        return res