public class GenerateParentheses {
public static List<String> gp(int n) {
List<List<String>> dp = new ArrayList<>(n+1);
dp.add(Arrays.asList(""));
dp.add(1, Arrays.asList("()"));
for (int i = 2; i <= n; i++) {
List<String> d = new ArrayList<>();
for (int j = 0; j <= i-1; j++) {
for (String left : dp.get(j)) {
for (String right : dp.get(i-1 - j)) {
String current = "(" + left + ")" + right;
d.add(current);
}
}
}
dp.add(d);
long distinct = d.stream().distinct().count();
if (distinct < d.size()) {
System.out.println("存在重复:&#