14#最长公共前缀（简单）

题目：

代码一：（1ms）

public String longestCommonPrefix(String[] strs){
        if (strs.length == 0) return "";
        String prefix = strs[0];
        for (int i = 1; i < strs.length; i++) {
            while(strs[i].indexOf(prefix)!=0){  //牛逼
                prefix = prefix.substring(0, prefix.length()-1);
                if (prefix.isEmpty()) return "";
            }
        }
        return prefix;
    }

代码二：（2ms）

public String longestCommonPrefix(String[] strs) {
        if (strs.length==0) {
            return "";
        }else if (strs.length==1){
            return strs[0];
        }
        StringBuilder sb = new StringBuilder();
        int count = 0;
        int min = strs[0].length();
        for (int i = 1; i < strs.length; i++) {
            min = Math.min(min, strs[i].length());
        }
        for (int i = 0; i < min; i++) {
            for (int j = 0; j < strs.length-1; j++) {
                if (strs[j].equals("")) return "";
                char c1 = strs[j].charAt(count);
                char c2 = strs[j+1].charAt(count);
                if (c1 != c2) {
                    return sb.toString();
                }else if (j + 1 == strs.length - 1) {
                    sb.append(c1);
                    count++;
                }
            }
        }
        return sb.toString();
    }