LeetCode(54)-Longest Common Prefix

题目：

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

思路：

• 题意：找出字符串的最大的公共前缀
• 思路是写一个比较的函数，遍历

-

代码：

public class Solution {
    public String longestCommonPrefix(String[] strs) {
        String result = null;
        if(strs == null){
            return null;
        }
        if(strs.length == 0){
            return "";
        }
        if(strs.length == 1){
            return strs[0];
        }
        result = see(strs[0],strs[1]);
        if(result == null){
            return null;
        }
        for(int a= 1;a < strs.length-1;a++){
            String tmp = see(strs[a],strs[a+1]);
            if(tmp == null){
                return null;
            }else{
                String tmp1 = see(tmp,result);
                if(tmp1 == null){
                    return null;
                }else{
                    result = tmp1;
                }
            }

        }
        return result;
    }
    public String see(String a,String b){
        StringBuffer sb = new StringBuffer();
        if(a == null || b == null){
            return null;
        }
        int n = Math.min(a.length(),b.length());
        for(int i = 0;i < n;i++){
            if(a.charAt(i) == b.charAt(i)){
                sb.append(a.charAt(i));
            }else{
                return sb.toString();
            }
        }
        return sb.toString();
    }
}