Alphabetical Strings

2000ms

524288K

Description:

A string $$$s$$$ of length $$$n$$$ ($$$1 \le n \le 26$$$) is called alphabetical if it can be obtained using the following algorithm:

first, write an empty string to $$$s$$$ (i.e. perform the assignment $$$s$$$ := "");
then perform the next step $$$n$$$ times;
at the $$$i$$$-th step take $$$i$$$-th lowercase letter of the Latin alphabet and write it either to the left of the string $$$s$$$ or to the right of the string $$$s$$$ (i.e. perform the assignment $$$s$$$ := $$$c+s$$$ or $$$s$$$ := $$$s+c$$$, where $$$c$$$ is the $$$i$$$-th letter of the Latin alphabet).

In other words, iterate over the $$$n$$$ first letters of the Latin alphabet starting from 'a' and etc. Each time we prepend a letter to the left of the string $$$s$$$ or append a letter to the right of the string $$$s$$$. Strings that can be obtained in that way are alphabetical.

For example, the following strings are alphabetical: "a", "ba", "ab", "bac" and "ihfcbadeg". The following strings are not alphabetical: "z", "aa", "ca", "acb", "xyz" and "ddcba".

From the given string, determine if it is alphabetical.

Input:

The first line contains one integer $$$t$$$ ($$$1 \le t \le 10^4$$$) — the number of test cases. Then $$$t$$$ test cases follow.

Each test case is written on a separate line that contains one string $$$s$$$. String $$$s$$$ consists of lowercase letters of the Latin alphabet and has a length between $$$1$$$ and $$$26$$$, inclusive.

Output:

Output $$$t$$$ lines, each of them must contain the answer to the corresponding test case. Output YES if the given string $$$s$$$ is alphabetical and NO otherwise.

You can output YES and NO in any case (for example, strings yEs, yes, Yes and YES will be recognized as a positive answer).

Sample Input:

11
a
ba
ab
bac
ihfcbadeg
z
aa
ca
acb
xyz
ddcba

Sample Output:

YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO

Note:

The example contains test cases from the main part of the condition.

Informação

Provedor Codeforces

Código CF1547B