Common Prefixes

题意翻译

给定 $n$ 个正整数 $a_{1,2,...,n}$，要求构造出 $n+1$ 个长度不超过 $200$ 的**非空**字符串 $s_1,s_2,...,s_{n+1}$，使得 $\forall 1 \leq i \leq n$，$s_i$ 和 $s_{i+1}$ 的最长公共**前缀**长度为 $a_i$。 多组数据，数据组数 $\leq 100$，$1 \leq n \leq 100,0 \leq a_i \leq 50, \sum n \leq 100$ 翻译 by Meatherm

题目描述

The length of the longest common prefix of two strings $ s = s_1 s_2 \ldots s_n $ and $ t = t_1 t_2 \ldots t_m $ is defined as the maximum integer $ k $ ( $ 0 \le k \le min(n,m) $ ) such that $ s_1 s_2 \ldots s_k $ equals $ t_1 t_2 \ldots t_k $ . Koa the Koala initially has $ n+1 $ strings $ s_1, s_2, \dots, s_{n+1} $ . For each $ i $ ( $ 1 \le i \le n $ ) she calculated $ a_i $ — the length of the longest common prefix of $ s_i $ and $ s_{i+1} $ . Several days later Koa found these numbers, but she couldn't remember the strings. So Koa would like to find some strings $ s_1, s_2, \dots, s_{n+1} $ which would have generated numbers $ a_1, a_2, \dots, a_n $ . Can you help her? If there are many answers print any. We can show that answer always exists for the given constraints.

输入输出格式

输入格式

Each test contains multiple test cases. The first line contains $ t $ ( $ 1 \le t \le 100 $ ) — the number of test cases. Description of the test cases follows. The first line of each test case contains a single integer $ n $ ( $ 1 \le n \le 100 $ ) — the number of elements in the list $ a $ . The second line of each test case contains $ n $ integers $ a_1, a_2, \ldots, a_n $ ( $ 0 \le a_i \le 50 $ ) — the elements of $ a $ . It is guaranteed that the sum of $ n $ over all test cases does not exceed $ 100 $ .

输出格式

For each test case: Output $ n+1 $ lines. In the $ i $ -th line print string $ s_i $ ( $ 1 \le |s_i| \le 200 $ ), consisting of lowercase Latin letters. Length of the longest common prefix of strings $ s_i $ and $ s_{i+1} $ has to be equal to $ a_i $ . If there are many answers print any. We can show that answer always exists for the given constraints.

输入输出样例

输入样例 #1

4
4
1 2 4 2
2
5 3
3
1 3 1
3
0 0 0

输出样例 #1

aeren
ari
arousal
around
ari
monogon
monogamy
monthly
kevinvu
kuroni
kurioni
korone
anton
loves
adhoc
problems

说明

In the $ 1 $ -st test case one of the possible answers is $ s = [aeren, ari, arousal, around, ari] $ . Lengths of longest common prefixes are: - Between $ \color{red}{a}eren $ and $ \color{red}{a}ri $ $ \rightarrow 1 $ - Between $ \color{red}{ar}i $ and $ \color{red}{ar}ousal $ $ \rightarrow 2 $ - Between $ \color{red}{arou}sal $ and $ \color{red}{arou}nd $ $ \rightarrow 4 $ - Between $ \color{red}{ar}ound $ and $ \color{red}{ar}i $ $ \rightarrow 2 $