public class Main { // Теперь имя совпадает с ожидаемым Main.java
    public static String longestCommonPrefix(String[] strs) {
        if (strs == null || strs.length == 0) return "";
 
        for (int i = 0; i < strs[0].length(); i++) {
            char c = strs[0].charAt(i);
            for (int j = 1; j < strs.length; j++) {
                if (i == strs[j].length() || strs[j].charAt(i) != c) {
                    return strs[0].substring(0, i);
                }
            }
        }
        return strs[0];
    }
 
    public static void main(String[] args) {
        String[] data = {"префикс", "преграда", "прекрасный"};
        System.out.println(longestCommonPrefix(data));
    }
}
 

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