Given an array of unique characters arr and a string str, Implement a function getShortestUniqueSubstring that finds the smallest substring of str containing all the characters in arr. Return "" (empty string) if such a substring doesn’t exist.
Come up with an asymptotically optimal solution and analyze the time and space complexities.
Example:
input: arr = ['x','y','z'], str = "xyyzyzyx"
output: "zyx"Constraints:
- [time limit] 5000ms
- [input] array.character arr
- 1 ≤ arr.length ≤ 30
- [input] string str
- 1 ≤ str.length ≤ 500
- [output] string
Solutions: