1092. Shortest Common Supersequence

https://leetcode.com/problems/shortest-common-supersequence

Description

Given two strings str1 and str2, return the shortest string that has both str1 and str2 as subsequences. If there are multiple valid strings, return any of them.

A string s is a subsequence of string t if deleting some number of characters from t (possibly 0) results in the string s.

Example 1:

**Input:** str1 = "abac", str2 = "cab"
**Output:** "cabac"
**Explanation:** 
str1 = "abac" is a subsequence of "cabac" because we can delete the first "c".
str2 = "cab" is a subsequence of "cabac" because we can delete the last "ac".
The answer provided is the shortest such string that satisfies these properties.

Example 2:

**Input:** str1 = "aaaaaaaa", str2 = "aaaaaaaa"
**Output:** "aaaaaaaa"

Constraints:

• 1 <= str1.length, str2.length <= 1000

• str1 and str2 consist of lowercase English letters.

ac