[leetcode]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: ["flower","flow","flight"]
Output: "fl"

Example 2:

Input: ["dog","racecar","car"]
Output: ""
Explanation: There is no common prefix among the input strings.

Note:

All given inputs are in lowercase letters a-z.

寻找最长公共前缀，可以将后面的字符串依次与首个字符串比较，有不同的就停止比较，将相同的部分存入数组返回

class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        if(strs.empty())
            return "";
        for(int i=0; i<strs[0].size(); i++)
        {
            for(int j=1; j<strs.size(); j++)
            {
                if(strs[j][i] != strs[0][i])
                    strs[0] = strs[0].substr(0,i);//复制长度为i的字符串
            }
        }
          return strs[0];  
        
    }
};