274| [H-Index](https://leetcode.com/problems/h-index/) | [C++](./C++/h-index.cpp) [Python](./Python/h-index.py) | _O(n)_ | _O(n)_ | Medium || Counting Sort |

280| [Wiggle Sort](https://leetcode.com/problems/wiggle-sort/) | [C++](./C++/wiggle-sort.cpp) [Python](./Python/wiggle-sort.py) | _O(n)_ | _O(1)_ | Medium |📖| |

324| [Wiggle Sort II](https://leetcode.com/problems/wiggle-sort-ii/) | [C++](./C++/wiggle-sort-ii.cpp) [Python](./Python/wiggle-sort-ii.py) | _O(n)_ on average | _O(1)_ | Medium | variant of [Sort Colors](https://leetcode.com/problems/sort-colors/) | Tri Partition |

406| [Queue Reconstruction by Height](https://leetcode.com/problems/queue-reconstruction-by-height/) | [C++](./C++/queue-reconstruction-by-height.cpp) [Python](./Python/queue-reconstruction-by-height.py) | _O(n * sqrt(n))_ | _O(n)_ | Medium | | |

451| [Sort Characters By Frequency](https://leetcode.com/problems/sort-characters-by-frequency/) | [C++](./C++/sort-characters-by-frequency.cpp) [Python](./Python/sort-characters-by-frequency.py) | _O(n)_ | _O(n)_ | Medium | | |

692| [Top K Frequent Words](https://leetcode.com/problems/top-k-frequent-words/) | [C++](./C++/top-k-frequent-words.cpp) [Python](./Python/top-k-frequent-words.py) | _O(n + klogk)_ on average | _O(n)_ | Medium | | Quick Select, Heap |