# 14. Longest Common Prefix

#### 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 lower-case English letters.

```python
class Solution:
    def longestCommonPrefix(self, strs: List[str]) -> str:
        prefix = ''
        for index in range(len(strs[0])):
            char = strs[0][index]
            for string in strs[1:]:
                if index >= len(string):
                    return prefix
                elif string[:index+1] != strs[0][:index+1]:
                    return prefix
            prefix += char
        return prefix
```