1092.shortest-common-supersequence.py

from lc import *

# https://leetcode.com/problems/shortest-common-supersequence/discuss/677141/Solutions-under-10-lines.-No-tricks-and-interview-friendly.

class Solution:
    def shortestCommonSupersequence(self, s1: str, s2: str) -> str:
       @lru_cache(maxsize=10000)
       def solve(i,j):
            if i == len(s1): return s2[j:]
            if j == len(s2): return s1[i:]
            if s1[i] == s2[j]: return s1[i]+solve(i+1,j+1)
            return min(s1[i]+solve(i+1,j),s2[j]+solve(i,j+1),key=len)
       return solve(0,0)

class Solution:
    def shortestCommonSupersequence(self, a: str, b: str) -> str:
        return(f:=lru_cache(9**5)(lambda i,j:a[i:]and b[j:]and(a[i]==b[j]and a[i]+f(i+1,j+1)or min(a[i]+f(i+1,j),b[j]+f(i,j+1),key=len))or a[i:]or b[j:]))(0,0)

test('''
1092. Shortest Common Supersequence
Hard

4943

72

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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.
Accepted
134,847
Submissions
226,404
''')