Longest Common Prefix（字元串數組的最長字首）leetcode14

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

.

code1：（本人的醜陋代碼）

public String longestCommonPrefix(String[] strs) {
        if(strs.length<1)
            return "";
        if(strs.length==1)
            return strs[0];
        int count=0;
        boolean isContinue=true;
        while(isContinue){
        for(int i=0;i<strs.length-1;i++){
            if((count>=strs[i].length()||count>=strs[i+1].length())||(strs[i].charAt(count)!=strs[i+1].charAt(count))){
                isContinue=false;
                break;
            }
        
        }           
        count++;
        }
        return strs[0].substring(0,count-1);
    }
           

code2：（比人家好看又快速的代碼）

public String longestCommonPrefix(String[] strs) {
            if (strs == null || strs.length == 0) return "";
        
        String pre = strs[0];

        for (int i = 1; i < strs.length; i++)
            while(strs[i].indexOf(pre) != 0)
                pre = pre.substring(0,pre.length()-1);
        return pre;
    }