CC150 chapter 1 總結
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HashTable: 實質是Array. 如何實現HashTable 在Java中
Here is the way that implments the hash table. A hashtable is a array of listnode. and the time complexity for all the basic operation including search, add and remove is O(1).
Here is how to implement the hashtable
http://math.hws.edu/javanotes/c10/ex3-ans.html.
when the number of the hashtable elements exceeds the 0.75* the length of the hashtable. then we need to rehash it.
ArrayList 是一個長度可變的數組
http://www.tutorialspoint.com/java/java_arraylist_class.htm
StringBuffer 實現了一個String數組，是一個String , 通常當對String多次操作時，選用StringBuffer 可以節省程序空間
1 題目 implement a determine a if all the chars in a string are unique, use the array for 32 bits. boolean judge = new judge[32];
2 decide if a string is a permutation of the other. use the int[]數組統計。注意首先進行長度的判斷
3 rotate a image.
4judge if the string is a rotated version of the other s1s1 ,s2 judge is substring.
method how to judge if this is substring.?
