Write a function to find the longest common prefix string amongst an array of strings

Simple Algorithm Will Go Like This:

Algorithm:Longest Common Prefix ( LCP)

1.Take a String From Array Whose length is Minimum else

  you might get exception if tries to access array element

  outside range.why this will work because if there exist 

  a common prefix then it will be the desired answer .

 Example like in case of "shash" ,"shank","shashank" LCP will be "sha"

 for this string "ab", "abc", "def" ,"defgh", "sha" LCP will be NULL

2.Keep Comparing reamining string character by character with 1st selected string  if mismatch occurs at any position i then append 1st string to output string.

Working Code

String findLongPrefix(String [] str) 

{
                StringBuilder strBuilder = new StringBuilder();
                
                char [] firstStr = str[0].toCharArray();
                for(int i=0; i< str[0].length(); i++ ) {
                        boolean found = true;
                        for(String str: str) {
                                if(str.charAt(i) != firstStr[i]) {
                                        found = false;
                                        break;
                                } 
                        }
                        
                        if(found) {
                                strBuilder.append(firstStr[i]);
                        } else 
                                break;
                        
                }
                
                return strBuilder.toString();
        }

Time Complexity O(N*M-1)=O( Where N is Length of 1st Smallest String 

and M is Number of remaining string in string array so it will run

upto length of array-1

Space Complexity O(1)