Codeforces Round 209 (Div. 2)
C
Prime Number
Codeforces
1900
原题
← BD →
翻译中…

Simon has a prime number $*x*$ and an array of non-negative integers $*a*_{1}, *a*_{2}, ..., *a*_{*n*}$.

翻译中…

Simon loves fractions very much. Today he wrote out number image on a piece of paper. After Simon led all fractions to a common denominator and summed them up, he got a fraction: image, where number $*t*$ equals $*x*^{*a*_{1} + *a*_{2} + ... + *a*_{*n*}}$. Now Simon wants to reduce the resulting fraction.

翻译中…

Help him, find the greatest common divisor of numbers $*s*$ and $*t*$. As GCD can be rather large, print it as a remainder after dividing it by number $1000000007$ ($10^{9} + 7$).

翻译中…

Input

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The first line contains two positive integers $*n*$ and $*x*$ ($1 ≤ *n* ≤ 10^{5}$, $2 ≤ *x* ≤ 10^{9}$) — the size of the array and the prime number.

翻译中…

The second line contains $*n*$ space-separated integers $*a*_{1}, *a*_{2}, ..., *a*_{*n*}$ ($0 ≤ *a*_{1} ≤ *a*_{2} ≤ ... ≤ *a*_{*n*} ≤ 10^{9}$).

翻译中…

Output

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Print a single number — the answer to the problem modulo $1000000007$ ($10^{9} + 7$).

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Note

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In the first sample image. Thus, the answer to the problem is $8$.

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In the second sample, image. The answer to the problem is $27$, as $351 = 13·27$, $729 = 27·27$.

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In the third sample the answer to the problem is $1073741824 *mod* 1000000007 = 73741817$.

翻译中…

In the fourth sample image. Thus, the answer to the problem is $1$.

翻译中…

样例

Input #1
2 2
2 2
Output #1
8
InputCopy OutputCopy
Input #2
3 3
1 2 3
Output #2
27
InputCopy OutputCopy
Input #3
2 2
29 29
Output #3
73741817
InputCopy OutputCopy
Input #4
4 5
0 0 0 0
Output #4
1
InputCopy OutputCopy
题目信息
题号
359C
时间限制
1 s
内存限制
256 MB
标签
数学
数论

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