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path: root/non_decreasing_subseq.cpp
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// 491. Non-decreasing Subsequences
#include "leetcode.h"

/*
 * given: integer array 'nums'
 * return: all possible different non-decreasing subsequences
 * of given array with at least two elements. return value
 * can be in any order
 */

class Solution {
public:
  vvd(int) findSubsequences(vector<int> &nums) {
    set<vector<int>> seqs = {vector<int>(0)};
    for (int i = 0; i < nums.size(); i++) {
      vvd(int) built(seqs.size());
      copy(seqs.begin(), seqs.end(), built.begin());
      for (auto s : built) {
        if (s.empty() || nums[i] >= s.back()) {
          s.push_back(nums[i]);
          seqs.insert(s);
        }
      }
    }
    vvd(int) ans;
    for (auto s : seqs)
      if (s.size() > 1)
        ans.push_back(s);
    return ans;
  }
};

int main() {
  Solution obj;
  vector<int> nums1 = {4, 6, 7, 7}, nums2 = {4, 4, 3, 2, 1};
  for (auto i : obj.findSubsequences(nums1))
    for (auto j : i)
      cout << j << ' ';
  cout << endl;
  for (auto i : obj.findSubsequences(nums2))
    for (auto j : i)
      cout << j << ' ';
}