用Swift 2.0去实现一些经典算法，在实现算法的过程中学习相关算法和Swift语法。
##Progress:
- Binary Search --Done
- Union and Find --Done
- LinkedList -- queue Done, stack Done.
- Elementary Sorts: Selection Sort, Insertion Sort, ShellSort -- Done.
- Mergesort -- Done.
- Quicksort -- Doing.
- Priority Queues
- Symbol Tables
- Balanced Search Trees
- Hash Table
- Undirected Graphs
- Directed Graphs
- Minimum Spanning Trees
- Dijkstra's shortest paths
- String sorts
- Tries