Making File Names Unique — LeetCode 1487 Python Solution

The problem

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].

Example

Input

names = ["pes","fifa","gta","pes(2019)"]

Output

["pes","fifa","gta","pes(2019)"]

Explanation

Let's see how the file system creates folder names:

Python solution

class Solution:
    def getFolderNames(self, names: List[str]) -> List[str]:
        d = defaultdict(int)
        for i, name in enumerate(names):
            if name in d:
                k = d[name]
                while f'{name}({k})' in d:
                    k += 1
                d[name] = k + 1
                names[i] = f'{name}({k})'
            d[names[i]] = 1
        return names

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 1487. Making File Names Unique is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Hash Table.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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