Check if Numbers Are Ascending in a Sentence — LeetCode 2042 Python Solution

The problem

A sentence is a list of tokens separated by a single space with no leading or trailing spaces. Every token is either a positive number consisting of digits 0-9 with no leading zeros, or a word consisting of lowercase English letters.

Example

Input

s = "1 box has 3 blue 4 red 6 green and 12 yellow marbles"

Output

true

Explanation

The numbers in s are: 1, 3, 4, 6, 12.

Python solution

class Solution:
    def areNumbersAscending(self, s: str) -> bool:
        pre = 0
        for t in s.split():
            if t[0].isdigit():
                if (cur := int(t)) <= pre:
                    return False
                pre = cur
        return True

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 2042. Check if Numbers Are Ascending in a Sentence is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

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

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