r,e,d三个字符,能否构成含有 cnt 个回文串的字符串 s原理:n个相同的字符构建的回文子串的个数为n(n+1)/2,其余的用edr补```public static void deal1() { Scanner sc = new Scanner(System.in); int x = sc.nextInt(); int n = (int) (Math.sqrt(2*x + 0.25) - 0.5); StringBuilder sb = new StringBuilder(); for (int i = 0; i < n; i++) { sb.append("r"); } n = n * (n+1) / 2; int y = (x - n) / 3; for (int i = 0; i < y; i++) { sb.append("edr"); } if (n + y * 3 == x) { System.out.println(sb); } else if (n + y * 3 + 1 == x) { sb.append("e"); System.out.println(sb); } else if (n + y * 3 + 2 == x) { sb.append("ed"); System.out.println(sb); }```