题目描述
Calculate factorial of a given number N.
Example 1:
Input: 5
Output: 120
Explanation: 1 * 2 * 3 * 4 * 5 = 120.
Your Task:
You don't need to read or print anything. Your task is to complete the function find_fact() which takes n as input parameter and returns factorial of N.
Expected Time Complexity: O(N)
Expected Space Complexity: O(1)
Constraints:
1 <= N <= 18
输入格式
见题面
输出格式
见题面
样例输入
5
样例输出
120