diff --git a/Dijkstra.java b/Dijkstra.java new file mode 100644 index 0000000..58a352c --- /dev/null +++ b/Dijkstra.java @@ -0,0 +1,70 @@ +import java.io.*; +import java.lang.*; +import java.util.*; + +class ShortestPath { + static final int V = 9; + int minDistance(int dist[], Boolean sptSet[]) + { + int min = Integer.MAX_VALUE, min_index = -1; + + for (int v = 0; v < V; v++) + if (sptSet[v] == false && dist[v] <= min) { + min = dist[v]; + min_index = v; + } + + return min_index; + } + + void printSolution(int dist[]) + { + System.out.println( + "Vertex \t\t Distance from Source"); + for (int i = 0; i < V; i++) + System.out.println(i + " \t\t " + dist[i]); + } + void dijkstra(int graph[][], int src) + { + int dist[] = new int[V]; + Boolean sptSet[] = new Boolean[V]; + + for (int i = 0; i < V; i++) { + dist[i] = Integer.MAX_VALUE; + sptSet[i] = false; + } + + dist[src] = 0; + + for (int count = 0; count < V - 1; count++) { + int u = minDistance(dist, sptSet); + + sptSet[u] = true; + + for (int v = 0; v < V; v++) + if (!sptSet[v] && graph[u][v] != 0 + && dist[u] != Integer.MAX_VALUE + && dist[u] + graph[u][v] < dist[v]) + dist[v] = dist[u] + graph[u][v]; + } + + printSolution(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 } }; + ShortestPath t = new ShortestPath(); + + t.dijkstra(graph, 0); + } +} diff --git a/Prims.java b/Prims.java new file mode 100644 index 0000000..edef788 --- /dev/null +++ b/Prims.java @@ -0,0 +1,80 @@ +import java.io.*; +import java.lang.*; +import java.util.*; + +class Prims { + + private static final int V = 5; + + int minKey(int key[], Boolean mstSet[]) + { + int min = Integer.MAX_VALUE, min_index = -1; + + for (int v = 0; v < V; v++) + if (mstSet[v] == false && key[v] < min) { + min = key[v]; + min_index = v; + } + + return min_index; + } + void printMST(int parent[], int graph[][]) + { + System.out.println("Edge \tWeight"); + for (int i = 1; i < V; i++) + System.out.println(parent[i] + " - " + i + "\t" + + graph[i][parent[i]]); + } + + void primMST(int graph[][]) + { + int parent[] = new int[V]; + int key[] = new int[V]; + + Boolean mstSet[] = new Boolean[V]; + + // Initialize all keys as INFINITE + for (int i = 0; i < V; i++) { + key[i] = Integer.MAX_VALUE; + mstSet[i] = false; + } + + key[0] = 0; + parent[0] = -1; + + for (int count = 0; count < V - 1; count++) { + int u = minKey(key, mstSet); + + mstSet[u] = true; + + for (int v = 0; v < V; v++) + if (graph[u][v] != 0 && mstSet[v] == false + && graph[u][v] < key[v]) { + parent[v] = u; + key[v] = graph[u][v]; + } + } + + printMST(parent, graph); + } + + public static void main(String[] args) + { + /* Let us create the following graph + 2 3 + (0)--(1)--(2) + | / \ | + 6| 8/ \5 |7 + | / \ | + (3)-------(4) + 9 */ + MST t = new MST(); + int graph[][] = new int[][] { { 0, 2, 0, 6, 0 }, + { 2, 0, 3, 8, 5 }, + { 0, 3, 0, 0, 7 }, + { 6, 8, 0, 0, 9 }, + { 0, 5, 7, 9, 0 } }; + + t.primMST(graph); + } +} \ No newline at end of file