LeetCode 14. Longest Common Prefix

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:

0 <= strs.length <= 200
0 <= strs[i].length <= 200
strs[i] consists of only lower-case English letters.

实现思路：

题目要求寻找一组字符串的最长公共前缀，方法就是双重循环，以第一个字符串为起始字符串，然后逐个对比，就是暴力法，其他方法的话之后可以再进行扩充。

AC代码：

class Solution {
	public:
		string longestCommonPrefix(vector<string>& strs) {
			if(strs.size()==0) return "";
			string prefix=strs[0];//用初始做前缀
			for(int i=0; i<strs.size(); i++) {
				string key=strs[i],temp;
				for(int j=0; j<key.length()&&j<prefix.length(); j++) {
					if(key[j]==prefix[j]) temp+=key[j];
					else break;
				}
				prefix=temp;
			}
			if(prefix.length()==0) return "";
			else return prefix;
		}
};