Package g1501_1600.s1575_count_all_possible_routes

Class Solution

java.lang.Object

g1501_1600.s1575_count_all_possible_routes.Solution

public class Solution
extends Object

1575 - Count All Possible Routes.<p>Hard</p> <p>You are given an array of <strong>distinct</strong> positive integers locations where <code>locations[i]</code> represents the position of city <code>i</code>. You are also given integers <code>start</code>, <code>finish</code> and <code>fuel</code> representing the starting city, ending city, and the initial amount of fuel you have, respectively.</p> <p>At each step, if you are at city <code>i</code>, you can pick any city <code>j</code> such that <code>j != i</code> and <code>0 <= j < locations.length</code> and move to city <code>j</code>. Moving from city <code>i</code> to city <code>j</code> reduces the amount of fuel you have by <code>|locations[i] - locations[j]|</code>. Please notice that <code>|x|</code> denotes the absolute value of <code>x</code>.</p> <p>Notice that <code>fuel</code> <strong>cannot</strong> become negative at any point in time, and that you are <strong>allowed</strong> to visit any city more than once (including <code>start</code> and <code>finish</code>).</p> <p>Return <em>the count of all possible routes from</em> <code>start</code> <em>to</em> <code>finish</code>. Since the answer may be too large, return it modulo <code>10⁹ + 7</code>.</p> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> locations = [2,3,6,8,4], start = 1, finish = 3, fuel = 5</p> <p><strong>Output:</strong> 4</p> <p><strong>Explanation:</strong> The following are all possible routes, each uses 5 units of fuel:</p> <p>1 -> 3</p> <p>1 -> 2 -> 3</p> <p>1 -> 4 -> 3</p> <p>1 -> 4 -> 2 -> 3</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> locations = [4,3,1], start = 1, finish = 0, fuel = 6</p> <p><strong>Output:</strong> 5</p> <p><strong>Explanation:</strong> The following are all possible routes:</p> <p>1 -> 0, used fuel = 1</p> <p>1 -> 2 -> 0, used fuel = 5</p> <p>1 -> 2 -> 1 -> 0, used fuel = 5</p> <p>1 -> 0 -> 1 -> 0, used fuel = 3</p> <p>1 -> 0 -> 1 -> 0 -> 1 -> 0, used fuel = 5</p> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> locations = [5,2,1], start = 0, finish = 2, fuel = 3</p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong> It is impossible to get from 0 to 2 using only 3 units of fuel since the shortest route needs 4 units of fuel.</p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 <= locations.length <= 100</code></li> <li><code>1 <= locations[i] <= 10⁹</code></li> <li>All integers in <code>locations</code> are <strong>distinct</strong>.</li> <li><code>0 <= start, finish < locations.length</code></li> <li><code>1 <= fuel <= 200</code></li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	countRoutes(int[] locations, int start, int finish, int fuel)

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

countRoutes

public int countRoutes(int[] locations,
 int start,
 int finish,
 int fuel)