Codeforces Round 449 (Div. 1)
D
Nephren Runs a Cinema
Codeforces
2900
原题
← CE →
翻译中…

Lakhesh loves to make movies, so Nephren helps her run a cinema. We may call it No. 68 Cinema.

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image

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However, one day, the No. 68 Cinema runs out of changes (they don't have 50-yuan notes currently), but Nephren still wants to start their business. (Assume that yuan is a kind of currency in Regulu Ere.)

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There are three types of customers: some of them bring exactly a 50-yuan note; some of them bring a 100-yuan note and Nephren needs to give a 50-yuan note back to him/her; some of them bring VIP cards so that they don't need to pay for the ticket.

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Now $*n*$ customers are waiting outside in queue. Nephren wants to know how many possible queues are there that they are able to run smoothly (i.e. every customer can receive his/her change), and that the number of 50-yuan notes they have after selling tickets to all these customers is between $*l*$ and $*r*$, inclusive. Two queues are considered different if there exists a customer whose type is different in two queues. As the number can be large, please output the answer modulo $*p*$.

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Input

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One line containing four integers $*n*$ ($1 ≤ *n* ≤ 10^{5})$, $*p*$ ($1 ≤ *p* ≤ 2·10^{9})$, $*l*$ and $*r*$ ($0 ≤ *l* ≤ *r* ≤ *n*$).

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Output

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One line indicating the answer modulo $*p*$.

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Note

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We use A, B and C to indicate customers with 50-yuan notes, customers with 100-yuan notes and customers with VIP cards respectively.

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For the first sample, the different possible queues that there are $2$ 50-yuan notes left are AAAB, AABA, ABAA, AACC, ACAC, ACCA, CAAC, CACA and CCAA, and the different possible queues that there are $3$ 50-yuan notes left are AAAC, AACA, ACAA and CAAA. So there are $13$ different queues satisfying the first sample. Similarly, there are $35$ different queues satisfying the second sample.

翻译中…

样例

Input #1
4 97 2 3
Output #1
13
InputCopy OutputCopy
Input #2
4 100 0 4
Output #2
35
InputCopy OutputCopy
题目信息
题号
896D
时间限制
2.5 s
内存限制
256 MB
标签
中国剩余定理
组合数学
数学
数论

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