#13204Count these Permutations
★★★★時間限制：2000 毫秒記憶體限制：64 MB
Let ⌊x⌋ be the floor of x. Count the number of permutations (a1, a2, . . . , an) of (1, 2, . . . , n) such that
|a1-1| + |a2-2| + ... + |an-n| = ⌊n2/2⌋
Input
A number of of inputs (≤ 1000), each start with the number of value of integer n (1 ≤ n ≤ 1000000).
Output
Output the number of permutations modulo 1000000007.
範例輸入 1
1 2 3
範例輸出 1
1 1 3
Pro 專屬功能： 查看這題在歷屆 CPE 出現過幾次 — 升級以解鎖.