EasyNo. 2042
Check if Numbers Are Ascending in a Sentence — LeetCode 2042 Python Solution
- Pattern
- Hash Map
- Topics
- String
- Reading time
- 2 min
- Source
- leetcode.com
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 TrueComplexity
- Time
- O(n)
- Space · auxiliary
- O(n)
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.
Related problems
| No. | Problem | Difficulty |
|---|---|---|
| 2047 | Number of Valid Words in a Sentence | Easy |
| 0006 | Zigzag Conversion | Medium |
| 0008 | String to Integer (atoi) | Medium |
| 0038 | Count and Say | Medium |
| 0058 | Length of Last Word | Easy |
| 0065 | Valid Number | Hard |
Frequently asked questions
- How hard is LeetCode 2042. Check if Numbers Are Ascending in a Sentence?
LeetCode 2042. Check if Numbers Are Ascending in a Sentence is rated Easy on LeetCode.
- What is the time complexity of LeetCode 2042. Check if Numbers Are Ascending in a Sentence?
The Python solution on this page runs in O(n).
- What is the space complexity of LeetCode 2042. Check if Numbers Are Ascending in a Sentence?
The Python solution on this page uses O(n) auxiliary space.
- What topics does LeetCode 2042. Check if Numbers Are Ascending in a Sentence cover?
LeetCode 2042. Check if Numbers Are Ascending in a Sentence is tagged String on LeetCode.