Oliver's Blog
Search…
⌃K

Double Factorial

ID: 771; easy; 二阶阶乘

Solution 1 (Java)

public class Solution {
/**
* @param n: the given number
* @return: the double factorial of the number
*/
public long doubleFactorial(int n) {
if (n == 0 || n == 1) return 1;
return (long)n * doubleFactorial(n - 2);
}
}

Notes

  • By definition of double factorial, the result is immediate.