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1 | 1 | packagecom.fishercoder.solutions; |
2 | 2 |
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3 | | -/** |
4 | | - * 1175. Prime Arrangements |
5 | | - * |
6 | | - * Return the number of permutations of 1 to n so that prime numbers are at prime indices (1-indexed.) |
7 | | - * (Recall that an integer is prime if and only if it is greater than 1, |
8 | | - * and cannot be written as a product of two positive integers both smaller than it.) |
9 | | - * Since the answer may be large, return the answer modulo 10^9 + 7. |
10 | | - * |
11 | | - * Example 1: |
12 | | - * Input: n = 5 |
13 | | - * Output: 12 |
14 | | - * Explanation: 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. |
15 | | - * |
16 | | - * Example 2: |
17 | | - * Input: n = 100 |
18 | | - * Output: 682289015 |
19 | | - * |
20 | | - * Constraints: |
21 | | - * 1 <= n <= 100 |
22 | | - * */ |
23 | 3 | publicclass_1175 { |
24 | 4 | publicstaticclassSolution1 { |
25 | 5 | publicintnumPrimeArrangements(intn) { |
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