MediumNo. 1807
Evaluate the Bracket Pairs of a String — LeetCode 1807 Python Solution
- Pattern
- Hash Map
- Topics
- Array, Hash Table, String
- Reading time
- 3 min
- Source
- leetcode.com
The problem
You are given a string s that contains some bracket pairs, with each pair containing a non-empty key. For example, in the string "(name)is(age)yearsold", there are two bracket pairs that contain the keys "name" and "age".
Example
- Input
- s = "(name)is(age)yearsold", knowledge = [["name","bob"],["age","two"]]
- Output
- "bobistwoyearsold"
- Explanation
- The key "name" has a value of "bob", so replace "(name)" with "bob".
Python solution
class Solution:
def evaluate(self, s: str, knowledge: List[List[str]]) -> str:
d = {a: b for a, b in knowledge}
i, n = 0, len(s)
ans = []
while i < n:
if s[i] == '(':
j = s.find(')', i + 1)
ans.append(d.get(s[i + 1 : j], '?'))
i = j
else:
ans.append(s[i])
i += 1
return ''.join(ans)Complexity
- Time
- O(n + m)
- Space · auxiliary
- O(L)
Pattern: Hash Map
Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 1807. Evaluate the Bracket Pairs of a String 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 1807. Evaluate the Bracket Pairs of a String?
LeetCode 1807. Evaluate the Bracket Pairs of a String is rated Medium on LeetCode.
- What is the time complexity of LeetCode 1807. Evaluate the Bracket Pairs of a String?
The Python solution on this page runs in O(n + m).
- What is the space complexity of LeetCode 1807. Evaluate the Bracket Pairs of a String?
The Python solution on this page uses O(L) auxiliary space.
- What topics does LeetCode 1807. Evaluate the Bracket Pairs of a String cover?
LeetCode 1807. Evaluate the Bracket Pairs of a String is tagged Array, Hash Table and String on LeetCode.