14_longest_common_prefix.java

class Solution {
    public String longestCommonPrefix(String[] strs) {
        if (strs.length == 1) {
            return strs[0];
        } else {
            String ans = commonPrefix(strs[0], strs[1]);
            for (int i = 2; i < strs.length; i++) {
                ans = commonPrefix(ans, strs[i]);
            }
            return ans;
        }
    }

    static public String commonPrefix(String str1, String str2) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < str1.length() && i < str2.length(); i++) {
            if (str1.charAt(i) == str2.charAt(i)) {
                sb.append(str1.charAt(i));
            } else {
                break;
            }
        }
        return sb.toString();
    }
}

/**
 * This is my personal record of solving Leetcode Problems. 
 * If you have any questions, please discuss them in [Issues](https://github.com/mengxinayan/leetcode/issues).
 * Copyright (C) 2020-2022  mengxinayan
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */