Optimal Partition of String - Problem
You are given a string s and need to find the most efficient way to partition it into substrings where every character in each substring appears exactly once.
Think of it as cutting the string into pieces where no piece contains duplicate characters. Your goal is to make the minimum number of cuts possible.
Example: If s = "abcabc", you could partition it as ["abc", "abc"] for 2 substrings, or ["a", "b", "c", "a", "b", "c"] for 6 substrings. The optimal solution uses 2 substrings.
Return the minimum number of substrings needed for such a partition.
Input & Output
example_1.py — Basic Case
$
Input:
s = "abcabc"
›
Output:
2
💡 Note:
The optimal partition is ["abc", "abc"]. When we reach the second 'a', we must start a new partition since 'a' already exists in the current substring.
example_2.py — No Duplicates
$
Input:
s = "abcdef"
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Output:
1
💡 Note:
All characters are unique, so the entire string forms one partition ["abcdef"].
example_3.py — All Same Characters
$
Input:
s = "aaaa"
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Output:
4
💡 Note:
Every character is a duplicate of the previous, so we need 4 partitions: ["a", "a", "a", "a"].
Constraints
- 1 ≤ s.length ≤ 104
- s consists of only lowercase English letters
- Each character must belong to exactly one substring
Visualization
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Understanding the Visualization
1
Start First Session
Begin with an empty reading room (hash set)
2
Add People
As people arrive, add them to current session if name is unique
3
Handle Duplicates
When someone with duplicate name arrives, start new session
4
Reset Room
Clear the room and add the duplicate person to fresh session
Key Takeaway
🎯 Key Insight: The moment we encounter a duplicate, we must start a new partition - no need to look ahead or try different combinations!
💡
Explanation
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