Prims algorithm for minimun spanning tree and KMP algorithm implemented in CPP

KMP_algo.cpp

@@ -0,0 +1,65 @@
+
+#include <iostream>
+#include <cstring>
+using namespace std;
+void preKMP(string pattern, int f[])
+{
+    int m = pattern.length(), k;
+    f[0] = -1;
+    for (int i = 1; i < m; i++)
+    {
+        k = f[i - 1];
+        while (k >= 0)
+        {
+            if (pattern[k] == pattern[i - 1])
+                break;
+            else
+                k = f[k];
+        }
+        f[i] = k + 1;
+    }
+}
+
+//check whether target string contains pattern 
+bool KMP(string pattern, string target)
+{
+    int m = pattern.length();
+    int n = target.length();
+    int f[m];     
+    preKMP(pattern, f);     
+    int i = 0;
+    int k = 0;        
+    while (i < n)
+    {
+        if (k == -1)
+        {
+            i++;
+            k = 0;
+        }
+        else if (target[i] == pattern[k])
+        {
+            i++;
+            k++;
+            if (k == m)
+                return 1;
+        }
+        else
+            k = f[k];
+    }
+    return 0;
+}
+
+int main()
+{
+    string tar = "Roshil is a coder who likes to code";
+    string pat = "code";
+    if (KMP(pat, tar))
+        cout<<"'"<<pat<<"' found in string '"<<tar<<"'"<<endl;
+    else
+        cout<<"'"<<pat<<"' not found in string '"<<tar<<"'"<<endl;
+    pat = "coding";
+    if (KMP(pat, tar))
+        cout<<"'"<<pat<<"' found in string '"<<tar<<"'"<<endl;
+    else
+        cout<<"'"<<pat<<"' not found in string '"<<tar<<"'"<<endl;
+    return 0;

prims_algo_for_mst.cpp

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+
+#include <bits/stdc++.h>
+using namespace std;
+
+
+#define V 5 
+
+// A utility function to find the vertex with 
+// minimum key value, from the set of vertices 
+// not yet included in MST 
+int minKey(int key[], bool mstSet[]) 
+{ 
+	// Initialize min value 
+	int min = INT_MAX, min_index; 
+
+	for (int v = 0; v < V; v++) 
+		if (mstSet[v] == false && key[v] < min) 
+			min = key[v], min_index = v; 
+
+	return min_index; 
+} 
+
+// A utility function to print the 
+// constructed MST stored in parent[] 
+void printMST(int parent[], int graph[V][V]) 
+{ 
+	cout<<"Edge \tWeight\n"; 
+	for (int i = 1; i < V; i++) 
+		cout<<parent[i]<<" - "<<i<<" \t"<<graph[i][parent[i]]<<" \n"; 
+} 
+
+// Function to construct and print MST for 
+// a graph represented using adjacency 
+// matrix representation 
+void primMST(int graph[V][V]) 
+{ 
+	// Array to store constructed MST 
+	int parent[V]; 
+
+	// Key values used to pick minimum weight edge in cut 
+	int key[V]; 
+
+	// To represent set of vertices included in MST 
+	bool mstSet[V]; 
+
+	// Initialize all keys as INFINITE 
+	for (int i = 0; i < V; i++) 
+		key[i] = INT_MAX, mstSet[i] = false; 
+
+	// Always include first 1st vertex in MST. 
+	// Make key 0 so that this vertex is picked as first vertex. 
+	key[0] = 0; 
+	parent[0] = -1; // First node is always root of MST 
+
+	// The MST will have V vertices 
+	for (int count = 0; count < V - 1; count++)
+	{ 
+		// Pick the minimum key vertex from the 
+		// set of vertices not yet included in MST 
+		int u = minKey(key, mstSet); 
+
+		// Add the picked vertex to the MST Set 
+		mstSet[u] = true; 
+
+		// Update key value and parent index of 
+		// the adjacent vertices of the picked vertex. 
+		// Consider only those vertices which are not 
+		// yet included in MST 
+		for (int v = 0; v < V; v++) 
+
+			// graph[u][v] is non zero only for adjacent vertices of m 
+			// mstSet[v] is false for vertices not yet included in MST 
+			// Update the key only if graph[u][v] is smaller than key[v] 
+			if (graph[u][v] && mstSet[v] == false && graph[u][v] < key[v]) 
+				parent[v] = u, key[v] = graph[u][v]; 
+	} 
+
+	// print the constructed MST 
+	printMST(parent, graph); 
+} 
+
+// Driver code
+int main() 
+{ 
+
+	int graph[V][V] = { { 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 } }; 
+
+	primMST(graph); 
+
+	return 0; 
+}