14 最长公共前缀

效率一般，但浅显易懂 

class Solution {
    public static String longestCommonPrefix(String[] strs) {
        //输入只包含a-z
		if(strs.length==0)return "";
		boolean sign = true;
		int count = strLongestLength(strs);
		int now = 0;
		while(now < count && sign) {
			if(!isCharAtEqual(strs, now)) {sign=false;break;}
			now++;
		}
		return strs[0].substring(0,now);
    }
	//获取字符串数组中最短字符串长度 作为比较次数的最大值
	public static int strLongestLength(String[] strs) {
		int arrayLength = strs.length;
		int count = 0 ;
		int min = 10000;
		while(count < arrayLength) {
			if(strs[count].length() < min) min=strs[count].length();
			count ++;
		}
		return min;
	}
	//遍历字符串数组 判断对应对应字符是否相等
	public static boolean isCharAtEqual(String[] strs , int point) {
		int arrayLength = strs.length;
		int count = 0 ;
		char buffer = strs[count].charAt(point);
		boolean sign = true;
		while(count < arrayLength-1) {
			count++;
			if(!(buffer == strs[count].charAt(point))) sign = false;
		}
		return sign;
	}
}