14. Longest Common Prefix【leetcode】

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

        for(int i =1;i<strs.length;i++){
            //用j计算最长串的长度
            int j=0;
           
            while(j<pr.length()&&j<strs[i].length()&&pr.charAt(j)==strs[i].charAt(j)){
                j++;
            }
            if(j==0){
                return "";
            }
            pr =pr.substring(0,j);
        }
        
        return pr;
    }
}