Leecode 491. 递增子序列 DFS+回溯+剪枝

原题链接：Leecode 491. 递增子序列

自己写的代码：每一个层次利用set去重

class Solution {
public:
    vector> res;
    vector v;
    void dfs(vector& nums,int start)
    {
        if(start==nums.size()) return;
        set s;
        for(int i=start;i
            if(s.count(nums[i])) continue;
            if(v.size()>0 && nums[i]0 && nums[i]>=v.back())
            {
                v.push_back(nums[i]);
                res.push_back(v);
            }
            if(v.size()==0) v.push_back(nums[i]);
            s.insert(nums[i]);
            dfs(nums,i+1);
            if(v.size()>0 ) v.pop_back();
        }
    }
    vector> findSubsequences(vector& nums) {
        dfs(nums,0);
        return res;
    }
};