codeforces#P587B. Duff in Beach
Duff in Beach
Description
While Duff was resting in the beach, she accidentally found a strange array b0, b1, ..., bl - 1 consisting of l positive integers. This array was strange because it was extremely long, but there was another (maybe shorter) array, a0, ..., an - 1 that b can be build from a with formula: bi = ai mod n where a mod b denoted the remainder of dividing a by b.
Duff is so curious, she wants to know the number of subsequences of b like bi1, bi2, ..., bix (0 ≤ i1 < i2 < ... < ix < l), such that:
- 1 ≤ x ≤ k
- For each 1 ≤ j ≤ x - 1,
- For each 1 ≤ j ≤ x - 1, bij ≤ bij + 1. i.e this subsequence is non-decreasing.
Since this number can be very large, she want to know it modulo 109 + 7.
Duff is not a programmer, and Malek is unavailable at the moment. So she asked for your help. Please tell her this number.
The first line of input contains three integers, n, l and k (1 ≤ n, k, n × k ≤ 106 and 1 ≤ l ≤ 1018).
The second line contains n space separated integers, a0, a1, ..., an - 1 (1 ≤ ai ≤ 109 for each 0 ≤ i ≤ n - 1).
Print the answer modulo 1 000 000 007 in one line.
Input
The first line of input contains three integers, n, l and k (1 ≤ n, k, n × k ≤ 106 and 1 ≤ l ≤ 1018).
The second line contains n space separated integers, a0, a1, ..., an - 1 (1 ≤ ai ≤ 109 for each 0 ≤ i ≤ n - 1).
Output
Print the answer modulo 1 000 000 007 in one line.
Samples
3 5 3
5 9 1
10
5 10 3
1 2 3 4 5
25
Note
In the first sample case, . So all such sequences are: , , , , , , , , and .