Package g1701_1800.s1786_number_of_restricted_paths_from_first_to_last_node

Class Solution

java.lang.Object

g1701_1800.s1786_number_of_restricted_paths_from_first_to_last_node.Solution

public class Solution
extends Object

1786 - Number of Restricted Paths From First to Last Node\. Medium There is an undirected weighted connected graph. You are given a positive integer `n` which denotes that the graph has `n` nodes labeled from `1` to `n`, and an array `edges` where each edges[i] = [ui, vi, weighti] denotes that there is an edge between nodes ui and vi with weight equal to weighti. A path from node `start` to node `end` is a sequence of nodes [z0, z1, z2, ..., zk] such that z0 = start and zk = end and there is an edge between zi and zi+1 where `0 <= i <= k-1`. The distance of a path is the sum of the weights on the edges of the path. Let `distanceToLastNode(x)` denote the shortest distance of a path between node `n` and node `x`. A **restricted path** is a path that also satisfies that distanceToLastNode(zi) > distanceToLastNode(zi+1) where `0 <= i <= k-1`. Return _the number of restricted paths from node_ `1` _to node_ `n`. Since that number may be too large, return it **modulo** 109 + 7. **Example 1:**  **Input:** n = 5, edges = \[\[1,2,3],[1,3,3],[2,3,1],[1,4,2],[5,2,2],[3,5,1],[5,4,10]] **Output:** 3 **Explanation:** Each circle contains the node number in black and its `distanceToLastNode value in blue.` The three restricted paths are: 1) 1 --> 2 --> 5 2) 1 --> 2 --> 3 --> 5 3) 1 --> 3 --> 5 **Example 2:**  **Input:** n = 7, edges = \[\[1,3,1],[4,1,2],[7,3,4],[2,5,3],[5,6,1],[6,7,2],[7,5,3],[2,6,4]] **Output:** 1 **Explanation:** Each circle contains the node number in black and its `distanceToLastNode value in blue.` The only restricted path is 1 --> 3 --> 7. **Constraints:** * 1 <= n <= 2 * 104 * n - 1 <= edges.length <= 4 * 104 * `edges[i].length == 3` * 1 <= ui, vi <= n * ui != vi * 1 <= weighti <= 105 * There is at most one edge between any two nodes. * There is at least one path between any two nodes.

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	countRestrictedPaths(int n, int[][] edges)

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

countRestrictedPaths

public int countRestrictedPaths(int n,
 int[][] edges)