Longest Common Prefix🦼

Question

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 lower-case English letters.

Java Solution

Two different solutions with two different time complexity.

O(n+s)
where n is the number of items in an array and s is the sum of all the characters given in each item of the array.

Code

O(n*m)
The time complexity is O(n*m) where n is the length of the array and m is the length of the longest string.

Code