태코놀로지

1. Motivation- Use array (static set) or linked-list (dynamic set)- They take linear time for search operation (i.e., proportional to the size)- Need better method → hash table(Array/Linked-list의 크기에 비례하는 탐색시간을 줄이는 방법이 필요) 2. Problem- When a record to be inserted maps to an already occupied slot in hash table, a collision occurs- You need a good hash function(높은 확률로 테이블 크기가 데이터보다 작기 때문에 한 슬롯에 배정..

Simple means to resolve collision- "Chaining": Use linked-lists. New key inserted at the head of a list.(충돌난 hash slot에 linked-list를 이용해서 주렁주렁 이어 달자. 단 head!) Why not inserted at the tail?(왜 tail이 아니라, head?) tail에 달기 위해서, tail까지 탐색이 필요한데,search operation of linked-list takes linear time(i.e., proportional to the size)

What is the property of a good hash function?1. Even distribution- Minimizes "collision" of keys 2. Irregularness- Avoids collision of patterned inputs(E.g., input of {0, 100, 200, 300} for the hash function h(k) = k % 100)

Advantages1. Size varies dynamically (dynamic set)- Unlike the static array (static set) you don't need to reserve a large memory in advance2. Insertion, deletion, merging, splitting take only constant time (cf. takes linear time for search operation)- In contrast, array takes linear time (i.e., proportional to the size) for these operations Disadvantages1. You cannot access an element using an ..