Package g1101_1200.s1175_prime_arrangements

Class Solution

java.lang.Object

g1101_1200.s1175_prime_arrangements.Solution

public class Solution
extends Object

1175 - Prime Arrangements.<p>Easy</p> <p>Return the number of permutations of 1 to <code>n</code> so that prime numbers are at prime indices (1-indexed.)</p> <p><em>(Recall that an integer is prime if and only if it is greater than 1, and cannot be written as a product of two positive integers both smaller than it.)</em></p> <p>Since the answer may be large, return the answer **modulo <code>10^9 + 7</code> **.</p> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> n = 5</p> <p><strong>Output:</strong> 12</p> <p><strong>Explanation:</strong> For example [1,2,5,4,3] is a valid permutation, but [5,2,3,4,1] is not because the prime number 5 is at index 1.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> n = 100</p> <p><strong>Output:</strong> 682289015</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 100</code></li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	numPrimeArrangements(int n)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Solution

public Solution()

Method Details

numPrimeArrangements

public int numPrimeArrangements(int n)