EasyNo. 2399
Check Distances Between Same Letters — LeetCode 2399 Python Solution
- Pattern
- Hash Map
- Topics
- Array, Hash Table, String
- Reading time
- 2 min
- Source
- leetcode.com
The problem
You are given a 0-indexed string s consisting of only lowercase English letters, where each letter in s appears exactly twice. You are also given a 0-indexed integer array distance of length 26.
Example
- Input
- s = "abaccb", distance = [1,3,0,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
- Output
- true
- Explanation
- - 'a' appears at indices 0 and 2 so it satisfies distance[0] = 1.
Python solution
class Solution:
def checkDistances(self, s: str, distance: List[int]) -> bool:
d = defaultdict(int)
for i, c in enumerate(map(ord, s), 1):
j = c - ord("a")
if d[j] and i - d[j] - 1 != distance[j]:
return False
d[j] = i
return TrueComplexity
- Time
- O(n), where n is the length of the string s
- Space · auxiliary
- O(|Σ|), where Σ is the character set, which in this case is the set of lowercase letters
Pattern: Hash Map
Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 2399. Check Distances Between Same Letters 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.
Related problems
| No. | Problem | Difficulty |
|---|---|---|
| 0049 | Group Anagrams | Medium |
| 0139 | Word Break | Medium |
| 0140 | Word Break II | Hard |
| 0336 | Palindrome Pairs | Hard |
| 0500 | Keyboard Row | Easy |
| 0522 | Longest Uncommon Subsequence II | Medium |
Frequently asked questions
- How hard is LeetCode 2399. Check Distances Between Same Letters?
LeetCode 2399. Check Distances Between Same Letters is rated Easy on LeetCode.
- What is the time complexity of LeetCode 2399. Check Distances Between Same Letters?
The Python solution on this page runs in O(n), where n is the length of the string s.
- What is the space complexity of LeetCode 2399. Check Distances Between Same Letters?
The Python solution on this page uses O(|Σ|), where \Sigma is the character set, which in this case is the set of lowercase letters auxiliary space.
- What topics does LeetCode 2399. Check Distances Between Same Letters cover?
LeetCode 2399. Check Distances Between Same Letters is tagged Array, Hash Table and String on LeetCode.