From db85993d0e5494fd056bd2ea0ceb007ddec4198f Mon Sep 17 00:00:00 2001
From: Simran Pattnaik <72657303+Simran1604@users.noreply.github.com>
Date: Tue, 5 Oct 2021 18:46:28 +0530
Subject: [PATCH] Add Dijskstra's Algorithm (Fixes #2470) (#2476)

---
 .../Graphs/DIJSKSTRAS_ALGORITHM.java          | 88 +++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 DataStructures/Graphs/DIJSKSTRAS_ALGORITHM.java

diff --git a/DataStructures/Graphs/DIJSKSTRAS_ALGORITHM.java b/DataStructures/Graphs/DIJSKSTRAS_ALGORITHM.java
new file mode 100644
index 000000000..d04a855e9
--- /dev/null
+++ b/DataStructures/Graphs/DIJSKSTRAS_ALGORITHM.java
@@ -0,0 +1,88 @@
+/*
+Refer https://www.geeksforgeeks.org/dijkstras-shortest-path-algorithm-greedy-algo-7/
+for better understanding 
+*/
+package DataStructures.Graphs;
+
+import java.util.*;
+import java.io.*;
+
+class dijkstras{
+
+    int k=9;
+    int minDist(int dist[], Boolean Set[])
+    {
+        int min = Integer.MAX_VALUE, min_index = -1;
+ 
+        for (int r = 0; r < k; r++)
+            if (Set[r] == false && dist[r] <= min) {
+                min = dist[r];
+                min_index = r;
+            }
+ 
+        return min_index;
+    }
+
+    void print(int dist[])
+    {
+        System.out.println("Vertex \t\t Distance");
+        for (int i = 0; i < k; i++)
+            System.out.println(i + " \t " + dist[i]);
+    }
+    void dijkstra(int graph[][], int src)
+    {
+        int dist[] = new int[k]; 
+        Boolean Set[] = new Boolean[k];
+ 
+        for (int i = 0; i < k; i++) {
+            dist[i] = Integer.MAX_VALUE;
+            Set[i] = false;
+        }
+ 
+        dist[src] = 0;
+ 
+        for (int c = 0; c < k - 1; c++) {
+           
+            int u = minDist(dist, Set);
+ 
+            Set[u] = true;
+ 
+            for (int v = 0; v < k; v++)
+ 
+                if (!Set[v] && graph[u][v] != 0 && dist[u] != Integer.MAX_VALUE && dist[u] + graph[u][v] < dist[v])
+                    dist[v] = dist[u] + graph[u][v];
+        }
+ 
+        print(dist);
+    }
+ 
+    public static void main(String[] args)
+    {
+        int graph[][] = new int[][] { { 0, 4, 0, 0, 0, 0, 0, 8, 0 },
+                                      { 4, 0, 8, 0, 0, 0, 0, 11, 0 },
+                                      { 0, 8, 0, 7, 0, 4, 0, 0, 2 },
+                                      { 0, 0, 7, 0, 9, 14, 0, 0, 0 },
+                                      { 0, 0, 0, 9, 0, 10, 0, 0, 0 },
+                                      { 0, 0, 4, 14, 10, 0, 2, 0, 0 },
+                                      { 0, 0, 0, 0, 0, 2, 0, 1, 6 },
+                                      { 8, 11, 0, 0, 0, 0, 1, 0, 7 },
+                                      { 0, 0, 2, 0, 0, 0, 6, 7, 0 } };
+        dijkstras t = new dijkstras();
+        t.dijkstra(graph, 0);
+    }//main
+
+}//djikstras
+
+/*
+OUTPUT :
+Vertex   Distance 
+0            0
+1            4
+2            12
+3            19
+4            21
+5            11
+6            9
+7            8
+8            14
+*/