14. Longest Common Prefix — LeetCode

Easy

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-

class Solution {
    public String longestCommonPrefix(String[] strs) {
        int count = 0;
        
        Arrays.sort(strs);
        String first_str = strs[0];
        String last_str = strs[strs.length - 1];
        for(int i=0;i<first_str.length();i++){
            if(first_str.charAt(i) == last_str.charAt(i))
                count++;
            else
                break;
        }
        
        return count == 0 ? "" :  first_str.substring(0,count);
        
    }
}