Longest common prefix
Write a function to find the longest common prefix string amongst an array of strings.
Pay attention to the corner case: strs can be empty.
We define cur to record the char at current round that is recorded by si.
If si equals to the current string’s length, we return the substring from 0 to si.
At the beginning of each round, cur is set as null.
So when cur is null, we know this is the first string to check in current round. We set cur as the letter of the current string at index si
For the following string,[Read More...]