Minimum Unique Shrink Window
Problem Description
Given a string `text` and an integer `distinctGoal`, find the length of the shortest contiguous substring that contains **exactly** `distinctGoal` distinct characters. If no such substring exists, return `-1`.
**Example 1:**
```
Input: text = "aabcbcdb", distinctGoal = 3
Output: 3
Explanation: The substring "bcd" (indices 4-6) has exactly 3 distinct characters and length 3.
```
**Example 2:**
```
Input: text = "xyzzyx", distinctGoal = 2
Output: 2
Explanation: "xy" or "yz" or "zy" or "yx" each contain exactly 2 distinct characters with length 2.
```
Constraints
- 1 <= text.length <= 10^5
- 1 <= distinctGoal <= 26
- text contains only lowercase English letters
Follow-up
Extend the solution to find the shortest substring containing exactly `distinctGoal` distinct characters each appearing at least twice.
Hints
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Solution
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