/*
 * @lc app=leetcode id=14 lang=java
 *
 * [14] Longest Common Prefix
 */

// @lc code=start
class Solution {
    public String longestCommonPrefix(String[] strs) {
        if(strs == null || strs.length == 0) {
            return "";
        }
        String r = strs[0];
        for(int i=1; i<strs.length;i++) {
            r = longestCommonPrefix(r, strs[i]);
        }
        return r;
    }

    private String longestCommonPrefix(String a, String b) {
        StringBuilder sb = new StringBuilder();
        for(int i = 0; i<a.length() && i<b.length();i++) {
            if(a.charAt(i) != b.charAt(i)) {
                break;
            }
            sb.append(a.charAt(i));
        }
        return sb.toString();
    }
}
// @lc code=end