How hard is LeetCode 2268. Minimum Number of Keypresses?

LeetCode 2268. Minimum Number of Keypresses is rated Medium on LeetCode.

What is the time complexity of LeetCode 2268. Minimum Number of Keypresses?

The Python solution on this page runs in O(n + |\Sigma| \times \log |\Sigma|).

What is the space complexity of LeetCode 2268. Minimum Number of Keypresses?

The Python solution on this page uses O(|\Sigma|) auxiliary space.

What topics does LeetCode 2268. Minimum Number of Keypresses cover?

LeetCode 2268. Minimum Number of Keypresses is tagged Greedy, Hash Table, String, Counting and Sorting on LeetCode.

Is LeetCode 2268. Minimum Number of Keypresses a premium problem?

Yes. LeetCode 2268. Minimum Number of Keypresses is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

Minimum Number of Keypresses — LeetCode 2268 Python Solution

MediumLeetCode PremiumGreedyHash TableStringCountingSorting

Problem: #2268
Pattern: Greedy
Reading time: 2 min
Source: leetcode.com

The problem

You have a keypad with 9 buttons, numbered from 1 to 9, each mapped to lowercase English letters. You can choose which characters each button is matched to as long as: All 26 lowercase English letters are mapped to.

Example

Input: s = "apple"
Output: 5
Explanation: One optimal way to setup your keypad is shown above.

Python solution

Python

class Solution:
    def minimumKeypresses(self, s: str) -> int:
        cnt = Counter(s)
        ans, k = 0, 1
        for i, x in enumerate(sorted(cnt.values(), reverse=True), 1):
            ans += k * x
            if i % 9 == 0:
                k += 1
        return ans

Complexity

Measure	Complexity
Time	O(n + \|\Sigma\| \times \log \|\Sigma\|)
Space	O(\|\Sigma\|) auxiliary

Pattern: Greedy

Take the locally best option every time — when you can prove that never costs you later. LeetCode 2268. Minimum Number of Keypresses is filed here because LeetCode tags it Greedy, which is the vocabulary this hub collects.

The greedy guide has the Python template for the pattern and the 346 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 2268. Minimum Number of Keypresses?: LeetCode 2268. Minimum Number of Keypresses is rated Medium on LeetCode.
What is the time complexity of LeetCode 2268. Minimum Number of Keypresses?: The Python solution on this page runs in O(n + |\Sigma| \times \log |\Sigma|).
What is the space complexity of LeetCode 2268. Minimum Number of Keypresses?: The Python solution on this page uses O(|\Sigma|) auxiliary space.
What topics does LeetCode 2268. Minimum Number of Keypresses cover?: LeetCode 2268. Minimum Number of Keypresses is tagged Greedy, Hash Table, String, Counting and Sorting on LeetCode.
Is LeetCode 2268. Minimum Number of Keypresses a premium problem?: Yes. LeetCode 2268. Minimum Number of Keypresses is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.