Codeforces Round 258 (Div. 2)
E
Devu and Flowers
Codeforces
2300
原题
← D→
翻译中…

Devu wants to decorate his garden with flowers. He has purchased $*n*$ boxes, where the $*i*$-th box contains $*f*_{*i*}$ flowers. All flowers in a single box are of the same color (hence they are indistinguishable). Also, no two boxes have flowers of the same color.

翻译中…

Now Devu wants to select exactly $*s*$ flowers from the boxes to decorate his garden. Devu would like to know, in how many different ways can he select the flowers from each box? Since this number may be very large, he asks you to find the number modulo $(10^{9} + 7)$.

翻译中…

Devu considers two ways different if there is at least one box from which different number of flowers are selected in these two ways.

翻译中…

Input

翻译中…

The first line of input contains two space-separated integers $*n*$ and $*s*$ ($1 ≤ *n* ≤ 20$, $0 ≤ *s* ≤ 10^{14}$).

翻译中…

The second line contains $*n*$ space-separated integers $*f*_{1}, *f*_{2}, ... *f*_{*n*}$ ($0 ≤ *f*_{*i*} ≤ 10^{12}$).

翻译中…

Output

翻译中…

Output a single integer — the number of ways in which Devu can select the flowers modulo $(10^{9} + 7)$.

翻译中…

Note

翻译中…

Sample 1. There are two ways of selecting $3$ flowers: ${1, 2}$ and ${0, 3}$.

翻译中…

Sample 2. There is only one way of selecting $4$ flowers: ${2, 2}$.

翻译中…

Sample 3. There are three ways of selecting $5$ flowers: ${1, 2, 2}$, ${0, 3, 2}$, and ${1, 3, 1}$.

翻译中…

样例

Input #1
2 3
1 3
Output #1
2
InputCopy OutputCopy
Input #2
2 4
2 2
Output #2
1
InputCopy OutputCopy
Input #3
3 5
1 3 2
Output #3
3
InputCopy OutputCopy
题目信息
题号
451E
时间限制
4 s
内存限制
256 MB
标签
位运算
组合数学
数论

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。