unique character in string

[librangel]

Implement an algorithm to determine if a string has all unique characters.
you can not use additional data structures?
请大侠指点
谢谢

[qiuzhenguang]

Use hash table to detect if there is repeated characters,When hash collision occurs,there must be characteres that is not unique.
The time complicity and space complexity are both O(n).

[librangel]

[Quote=引用 1 楼 qiuzhenguang 的回复:]
Use hash table to detect if there is repeated characters,When hash collision occurs,there must be characteres that is not unique.
The time complicity and space complexity are both O(n).
[/Quote]

不能用多于的data structure啊~~

[天下第一好大人]

如果允许破坏原来的数据，那么可以排序，在排序中判断是否有相等的，相等则跳出。

由于排序可以达到O(nlogn),所以这个方法不会低于O(nlogn)。