先对字符串排序，第一个和最后一个差别最大，计算差别最大的最小公共子串变为全局的最小公共子串

package com.bupt;

import java.util.Arrays;

public class T14 {
    public String longestCommonPrefix(String[] strs) {
        Arrays.sort(strs);
        String a = strs[0];
        String b = strs[strs.length-1];
        int min = Math.min(a.length(),b.length());
        int commonLength = 0 ;
        for (int i = 0; i < min; i++) {
            if(a.substring(0,i+1).equals(b.substring(0,i+1))){
                commonLength++;
            }else{
                break;
            }
        }
        if(commonLength==0) return "";
        return a.substring(0,commonLength);
    }
    public static void main(String[] args) {
        String []strs = {"1flower","2flow","3flight"};
        System.out.println(new T14().longestCommonPrefix(strs));
    }
}