# No-Category

## Quick Select

<http://www.cs.yale.edu/homes/aspnes/pinewiki/QuickSelect.html>

Median of median <https://en.wikipedia.org/wiki/Median_of_medians>

* No. 215 Kth Largest Element in an Array

## Graph

Should be in Data Structure. but not many leetcode problems.

* [310. Minimum Height Trees](https://leetcode.com/problems/minimum-height-trees/): remove leaves

## Not solved

1. Cut Off Trees for Golf Event

## Convex Hull

* No. 469 Convex Polygon(Check): Degree of corner is less than 180 degree
* No. 381: Insert Delete GetRandom O(1) - Duplicates allowed

## Boring:

* 1. Self Dividing Numbers: check all

## Many Cases:

* No. 65: Valid Number

* No. 8:  String to Integer (atoi)

* No.13: Roman to Integer
  * Right from left

* No. 717: 1-bit and 2-bit Characters

* [54. Spiral Matrix](https://leetcode.com/problems/spiral-matrix/)

* [605. Can Place Flowers](https://leetcode.com/problems/can-place-flowers/)

Cannot Categorize

* No. 283: Move Zeros. (swap to save time)

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