1487.Making File Names Unique¶
Tags: Medium
Hash Table
String
Links: https://leetcode.com/problems/making-file-names-unique/
Given an array of strings names
of size n
. You will create n
folders in your file system such that, at the ith
minute, you will create a folder with the name names[i]
.
Since two files cannot have the same name, if you enter a folder name which is previously used, the system will have a suffix addition to its name in the form of (k)
, where, k
is the smallest positive integer such that the obtained name remains unique.
Return an array of strings of length n
where ans[i]
is the actual name the system will assign to the ith
folder when you create it.
Example 1:
Input: names = ["pes","fifa","gta","pes(2019)"]
Output: ["pes","fifa","gta","pes(2019)"]
Explanation: Let's see how the file system creates folder names:
"pes" --> not assigned before, remains "pes"
"fifa" --> not assigned before, remains "fifa"
"gta" --> not assigned before, remains "gta"
"pes(2019)" --> not assigned before, remains "pes(2019)"
Example 2:
Input: names = ["gta","gta(1)","gta","avalon"]
Output: ["gta","gta(1)","gta(2)","avalon"]
Explanation: Let's see how the file system creates folder names:
"gta" --> not assigned before, remains "gta"
"gta(1)" --> not assigned before, remains "gta(1)"
"gta" --> the name is reserved, system adds (k), since "gta(1)" is also reserved, systems put k = 2. it becomes "gta(2)"
"avalon" --> not assigned before, remains "avalon"
Example 3:
Input: names = ["onepiece","onepiece(1)","onepiece(2)","onepiece(3)","onepiece"]
Output: ["onepiece","onepiece(1)","onepiece(2)","onepiece(3)","onepiece(4)"]
Explanation: When the last folder is created, the smallest positive valid k is 4, and it becomes "onepiece(4)".
Example 4:
Input: names = ["wano","wano","wano","wano"]
Output: ["wano","wano(1)","wano(2)","wano(3)"]
Explanation: Just increase the value of k each time you create folder "wano".
Example 5:
Input: names = ["kaido","kaido(1)","kaido","kaido(1)"]
Output: ["kaido","kaido(1)","kaido(2)","kaido(1)(1)"]
Explanation: Please note that system adds the suffix (k) to current name even it contained the same suffix before.
Constraints:
1 <= names.length <= 5 * 10^4
1 <= names[i].length <= 20
names[i]
consists of lower case English letters, digits and/or round brackets.
用一个hash table
来存储某个字符串下一个最小可用的整数,如果某个字符串最开始不存在于哈希表里,那么它的下一个最小可用的整数是1,如果存在,那么就形成names[i](k)
的形式,查看其是否存在于哈希表里,知道不存在,得到这个k
,同时也需要把这个names[i](k)
插入到哈希表里面。
需要保证文件名唯一,注意第五个测试用例。设字符串长度为l
,数组长度为n
,那么时间复杂度为O(nl)。