Longest Common Prefix (Java)

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

注：在输入字符串个数为1时原样输出 

length()<1或无相同前缀的输出""

Source

public static String longestCommonPrefix(String[] strs) {
		char flag;
		int k = -1;
		int len = Integer.MAX_VALUE;
		if(strs.length < 1) return "";
		
		for(int i = 0; i < strs.length ; i++)     //strs.length用于表示字符串数组中字符串的个数
		{
			if(strs[i].length() < len) len = strs[i].length();
		}
		Step:										//跳出多重循环
		for(int i = 0; i < len ; i++)
		{
			flag = strs[0].charAt(i);
			for(int j = 1; j < strs.length ; j++)
			{
				if(strs[j].charAt(i) != flag ) break Step;
				
			}
			k++;
		}
		if(k == -1) return "";
		else return strs[0].substring(0,k+1);		//substring用于截取字符串的子串
		
	
	}