Longest Common Prefix

easyStrings+10 XPTime limit 2s

Find the longest string that is a prefix of every word in the list.

Input:

line 1: n
next n lines: one word each (lowercase letters)

Output: the longest common prefix, or - if the words share no prefix at all.

Constraints: 1 ≤ n ≤ 10⁴, 1 ≤ word length ≤ 200.

Think about it: compare character by character across all words ("vertical scanning"). Neat trick: after sorting, you only need to compare the first and the last word.

Sample input 1

3
flower
flow
flight

Sample output 1

fl

Sample input 2

3
dog
racecar
car

Sample output 2

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Read input from standard input and print the answer to standard output. Your code runs in a secure sandbox against the samples (Run) and hidden tests (Submit).

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