CSES - Two Sets II | Hai tập hợp II

View as PDF



Authors:
Problem types
Points: 1600 (p) Time limit: 1.0s Memory limit: 512M Input: stdin Output: stdout

Your task is to count the number of ways numbers \(1,2,\ldots, n\) can be divided into two sets of equal sum.

For example, if \(n=7\), there are four solutions:

  • \(\{1,3,4,6\}\) and \(\{2,5,7\}\)
  • \(\{1,2,5,6\}\) and \(\{3,4,7\}\)
  • \(\{1,2,4,7\}\) and \(\{3,5,6\}\)
  • \(\{1,6,7\}\) and \(\{2,3,4,5\}\)

Input

  • The only input line contains an integer \(n\).

Output

  • Print the answer modulo \(10^9+7\).

Constraints

  • \(1 \leq n \leq 500\)

Example

Sample input

7 

Sample output

4


Comments (7)

Most recent
Loading comments...