Sort and Tree

2014 Spring CS32 DiscussionJungseock Joo

- From wikipedia.com

Selection Sort

Bubble Sort

Merge Sort

Quicksort

Time Complexity

• Divide-and-conquer : O(n log2n)• Otherwise, O(n2)

When use what?

• In practice– std::sort();– If n is small, you may choose simpler ones.

• Considerations– Worst-case performance?– Already sorted? Partially-already sorted? Reversed

order?– # of comparisons vs. # of swap/shift

Binary Search Tree

• Find 7?

Binary Search Tree

• Find 7? – O(log n)

Depth of tree~ log nIf balanced.

Binary Search Tree

• But, O(n) in unbalanced BSTs– Depth >> log n

Depth of tree~ nIf unbalanced.

Code example

• Sum of items?

Tree Traversal