491. 非递减子序列

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题目链接：491. 非递减子序列

代码如下：

class Solution {
public:void backtracking(vector<int>& nums,int index){if(path.size()>1)   res.emplace_back(path);if(index>=nums.size())  return;unordered_set<int> uset;//进行去重for(int i=index;i<nums.size();i++){if((!path.empty()&&nums[i]<path.back())||uset.find(nums[i])!=uset.end())continue;uset.insert(nums[i]);path.emplace_back(nums[i]);backtracking(nums,i+1);//进行递归path.pop_back();//回溯}}vector<vector<int>> findSubsequences(vector<int>& nums) {backtracking(nums,0);return res;}
public:vector<vector<int>> res;vector<int> path;
};