当给定值 n 和 r 时查找排列的 Java 程序
排列是指可以安排或以某种方式对齐的成员的数量。从 n 个元素中排列出 k 个元素的公式为 -
nPk = n! / (n - k)!
算法
1. Define values for n and r. 2. Calculate factorial of n and (n-r). 3. Divide factorial(n) by factorial(n-r). 4. Display result as a permutation.
示例
import java.util.Scanner; public class Permutation { static int factorial(int n) { int f; for(f = 1; n > 1; n--){ f *= n; } return f; } static int npr(int n,int r) { return factorial(n)/factorial(n-r); } public static void main(String args[]){ Scanner sc = new Scanner(System.in); System.out.println("Enter the value of n :"); int n = sc.nextInt(); System.out.println("Enter the value of r :"); int r = sc.nextInt(); System.out.println("npr value is ::"+npr(n,r)); } }
输出
Enter the value of n : 4 Enter the value of r : 3 npr value is ::24
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