Given a weighted undirected connected graph with N nodes and M edges. Some of the nodes are marked as good. The task is to find the shortest distance between any pair of two different good nodes.
Note: Nodes marked as yellow in the below examples are considered to be good nodes.
Output : 7 Explanation : Pairs of Good Nodes and distance between them are: (1 to 3) -> distance: 7, (3 to 5) -> distance: 9, (1 to 5) -> distance: 16, out of which 7 is the minimum. Input :
Output : 4
Approach: Let us start by thinking of an algorithm to solve a simpler version of the given problem wherein all edges are of weight 1.
- Pick a random good node and perform a BFS from this point and stop at the first level say which contains another good node.
- We know that the minimum distance between any two good nodes can’t be more than s. So we again take a good node at random which is not already taken before and perform a BFS again. If we don’t find any special node in s distance, we terminate the search. If we do, then we update the value of s and repeat the procedure with some other special node taken at random.
We can apply a similar algorithm when weights are multiple.
Below is the implementation of the above approach:
- Finding shortest path between any two nodes using Floyd Warshall Algorithm
- Minimum distance between any special pair in the given array
- Find count of pair of nodes at even distance
- Check if given path between two nodes of a graph represents a shortest paths
- Queries to find distance between two nodes of a Binary tree
- Queries to find distance between two nodes of a Binary tree - O(logn) method
- Find distance between two nodes in the given Binary tree for Q queries
- Program to find the maximum difference between the index of any two different numbers
- Shortest distance between a Line and a Point in a 3-D plane
- Shortest distance between a point and a circle
- Find Shortest distance from a guard in a Bank
- Find two disjoint good sets of vertices in a given graph
- Count nodes within K-distance from all nodes in a set
- Construct a graph which does not contain any pair of adjacent nodes with same value
- Find maximum distance between any city and station
- Distance of chord from center when distance between center and another equal length chord is given
- Shortest distance to every other character from given character
- Shortest distance from the centre of a circle to a chord
- Sum of shortest distance on source to destination and back having at least a common vertex
- Print the path between any two nodes of a tree | DFS
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.