# 1487. Making File Names Unique
###### tags: `Leetcode` `Medium` `Microsoft`
Link: https://leetcode.com/problems/making-file-names-unique/
## 思路
有点麻烦的一道题
基本上是把所有出现过的名字都存成map key，val是下一个available的index，然后一个一个试这个index可不可用
**要注意怎么把list of string变成string array ```ans.toArray(new String[0])```**
## Code

class Solution {
    public String[] getFolderNames(String[] names) {
        Map<String, Integer> map = new HashMap<>();
        List<String> ans = new ArrayList<>();
        for(String name:names){
            if(map.containsKey(name)){
                int val = map.get(name);
                StringBuilder sb = new StringBuilder(name);
                
                sb.append('(');
                sb.append(val);
                sb.append(')');
                
                while(map.containsKey(sb.toString())){
                    val++;
                    sb = new StringBuilder(name);
                    sb.append('(');
                    sb.append(val);
                    sb.append(')');
                }
                map.put(sb.toString(), 1);
                map.put(name, val+1);
                ans.add(sb.toString());
            }
            else{
                map.put(name, 1);
                ans.add(name);
            }
        }
        return ans.toArray(new String[0]);
    }
}