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

Python

class Solution(object):
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        if "" in strs or len(strs) == 0:
            return ""
        elif len(strs) == 1:
            return strs[0]
        else:
            result = strs[[len(str(item)) for item in strs].index(min([len(str(item)) for item in strs]))]
            while result in strs:
                strs.remove(result)
            if strs:
                for strs_each in strs:
                    for index in range(min(len(result), len(strs_each))):
                        if strs_each[index] != result[index]:
                            result = result[:index]
                            break
            return result

Java（参考九章算法）

class Solution {
    public String longestCommonPrefix(String[] strs) {
        if(strs == null || strs.length == 0){
            return "";
        }
        String result = strs[0];
        for(int i = 1; i < strs.length; i++){
            int j = 0;
            while(j < strs[i].length() && j < result.length() && strs[i].charAt(j) == result.charAt(j)){
                j++;
            }
            if(j == 0){
                return "";
            }
            result = result.substring(0, j);
        }
        return result;
    }
}