Package g1301_1400.s1359_count_all_valid_pickup_and_delivery_options

Class Solution

java.lang.Object

g1301_1400.s1359_count_all_valid_pickup_and_delivery_options.Solution

public class Solution
extends Object

1359 - Count All Valid Pickup and Delivery Options.<p>Hard</p> <p>Given <code>n</code> orders, each order consist in pickup and delivery services.</p> <p>Count all valid pickup/delivery possible sequences such that delivery(i) is always after of pickup(i).</p> <p>Since the answer may be too large, return it modulo 10^9 + 7.</p> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> n = 1</p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong> Unique order (P1, D1), Delivery 1 always is after of Pickup 1.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> n = 2</p> <p><strong>Output:</strong> 6</p> <p><strong>Explanation:</strong> All possible orders:</p> <p>(P1,P2,D1,D2), (P1,P2,D2,D1), (P1,D1,P2,D2), (P2,P1,D1,D2), (P2,P1,D2,D1) and (P2,D2,P1,D1).</p> <p>This is an invalid order (P1,D2,P2,D1) because Pickup 2 is after of Delivery 2.</p> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> n = 3</p> <p><strong>Output:</strong> 90</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 500</code></li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	countOrders(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

countOrders

public int countOrders(int n)