Given a array of N strings, find the longest common prefix among all strings present in the array.

Example 1:

Input:
N = 4
arr[] = {geeksforgeeks, geeks, geek,
         geezer}
Output: gee
Explanation: "gee" is the longest common
prefix in all the given strings.

​Example 2:

Input: 
N = 2
arr[] = {hello, world}
Output: -1
Explanation: There's no common prefix
in the given strings.

Your Task:
You don't need to read input or print anything. Your task is to complete the function longestCommonPrefix() which takes the string array arr[] and its size N as inputs and returns the longest common prefix common in all the strings in the array. If there's no prefix common in all the strings, return "-1".

Expected Time Complexity: O(N*max(|arr_i|)).
Expected Auxiliary Space: O(max(|arr_i|)) for result.

Constraints:
1<=N<=10³
1<=|arr_i|<=10³