Logical Moos
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긴 and/or 불리언 식이 주어질 때, 홀수 위치에서 시작하고 끝나는 연속 구간을 지우고 그 자리에 true 또는 false 하나를 넣어 전체 식을 원하는 값으로 만들 수 있는지 묻는 질의에 답한다.
문제
Farmer John has a boolean statement that is keywords long (, odd). Only true or false appear in odd positions, while only and and or appear in even positions.
A phrase of the form , where and are either true or false, and is and or or, evaluates as follows:
and: This evaluates to true if both and are true, and false otherwise.or: This evaluates to true if either or is true, and false otherwise.
When evaluating the statement, FJ has to take the order of precedence in Moo Language into account. Similar to C++, and takes priority over or. More specifically, to evaluate the statement, repeat the following step until the statement consists of only one keyword.
- If the statement contains an
and, choose any of them and replace the phrase surrounding it with its evaluation. - Otherwise, the statement contains an
or. Choose any of them and replace the phrase surrounding it with its evaluation.
It may be proven that if multiple phrases can be evaluated during a given step, it does not matter which one is chosen; the statement will always evaluate to the same value.
FJ has queries. In each query, he gives you two integers and (, and are both odd), and deletes the segment from keyword to keyword inclusive. In turn, he wishes to replace the segment he just deleted with just one simple true or false so that the whole statement evaluates to a certain boolean value. Help FJ determine if it's possible!
입력
The first line contains and .
The next line contains strings, a valid boolean statement.
The following lines contain two integers and , and a string true or false, denoting whether he wants the whole statement to evaluate to true or false.
출력
Output a string of length , where the 'th character is Y if the 'th query is possible, otherwise N.