CF1547B.Alphabetical Strings
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题目描述
A string s of length n ( 1≤n≤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.
输入格式
The first line contains one integer t ( 1≤t≤104 ) — 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.
输出格式
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).
输入输出样例
输入#1
11 a ba ab bac ihfcbadeg z aa ca acb xyz ddcba
输出#1
YES YES YES YES YES NO NO NO NO NO NO
说明/提示
The example contains test cases from the main part of the condition.