LeetCode Solution - Problem Longest Common Prefix

• Write a function to find the longest common prefix string amongst an array of strings.
• If there is no common prefix, return an empty string "".

Example 1:

Input: strs = ["flower","flow","flight"]
Output: "fl"

Example 2:

Input: strs = ["dog","racecar","car"]
Output: ""
Explanation: There is no common prefix among the input strings.

Constraints:

• 1 <= strs.length <= 200 
• 0 <= strs[i].length <= 200 
• strs[i] consists of only lowercase English letters. 

Solution:

Java:

class Solution {
    public String longestCommonPrefix(String[] strs) {
       if (strs.length == 0) {
           return "";
       }
       String prefix = strs[0];
       for (int i = 1; i < strs.length; i++) {
           while (strs[i].indexOf(prefix) != 0) {
               prefix = prefix.substring(0, prefix.length() - 1);
               if (prefix.isEmpty()) return "";
           }
       }
       return prefix;
    }
}

Python:

class Solution:
    def longestCommonPrefix(self, strs: List[str]) -> str:
        res = ""
        for a in zip(*strs):
            if len(set(a)) == 1: 
                res += a[0]
            else: 
                return res
        return res