Check if Number Has Equal Digit Count and Digit Value — LeetCode 2283 Python Solution

The problem

You are given a 0-indexed string num of length n consisting of digits. Return true if for every index i in the range 0 <= i < n, the digit i occurs num[i] times in num, otherwise return false.

Example

Input

num = "1210"

Output

true

Explanation

num[0] = '1'. The digit 0 occurs once in num.

Python solution

class Solution:
    def digitCount(self, num: str) -> bool:
        cnt = Counter(int(x) for x in num)
        return all(cnt[i] == int(x) for i, x in enumerate(num))

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 2283. Check if Number Has Equal Digit Count and Digit Value is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Hash Table and Counting.

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

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