|
||||||||||
permutationTime Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 384 Accepted Submission(s): 221 Problem Description Permutation plays a very important role in Combinatorics. For example ,1 2 3 4 5 and 1 3 5 4 2 are both 5-permutations. As everyone's known, the number of n-permutations is n!. According to their magnitude relatives ,if we insert the sumbols "<" or ">"between every pairs of consecutive numbers of a permutations,we can get the permutations with symbols. For example,1 2 3 4 5 can be changed to 1<2<3<4<5, 1 3 5 4 2 can be changed to 1<3<5>4>2. Now it's yout task to calculate the number of n-permutations with k"<"symbol. Maybe you don't like large numbers ,so you should just geve the result mod 2009. Input Input may contai multiple test cases. Each test case is a line contains two integers n and k .0<n<=100 and 0<=k<=100. The input will terminated by EOF. Output The nonegative integer result mod 2007 on a line. Sample Input
Sample Output
Source | ||||||||||
|