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DisjointSetUnion.c
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DisjointSetUnion.c
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#include <stdio.h>
#include <stdlib.h>
// Structure to represent an edge in the graph
struct Edge {
int src, dest;
};
// Structure to represent a graph
struct Graph {
int V, E;
struct Edge* edges;
};
// Structure to represent a subset for union-find
struct Subset {
int parent;
int rank;
};
// Function to create a graph
struct Graph* createGraph(int V, int E) {
struct Graph* graph = (struct Graph*)malloc(sizeof(struct Graph));
graph->V = V;
graph->E = E;
graph->edges = (struct Edge*)malloc(E * sizeof(struct Edge));
return graph;
}
// Function to find the parent of a node in a subset
int find(struct Subset subsets[], int i) {
if (subsets[i].parent != i) {
subsets[i].parent = find(subsets, subsets[i].parent);
}
return subsets[i].parent;
}
// Function to perform union of two subsets
void unionSets(struct Subset subsets[], int x, int y) {
int xroot = find(subsets, x);
int yroot = find(subsets, y);
if (subsets[xroot].rank < subsets[yroot].rank) {
subsets[xroot].parent = yroot;
} else if (subsets[xroot].rank > subsets[yroot].rank) {
subsets[yroot].parent = xroot;
} else {
subsets[yroot].parent = xroot;
subsets[xroot].rank++;
}
}
// Function to find the number of connected components
int countComponents(struct Graph* graph) {
int V = graph->V;
struct Edge* edges = graph->edges;
// Create V subsets with single elements
struct Subset* subsets = (struct Subset*)malloc(V * sizeof(struct Subset));
for (int v = 0; v < V; v++) {
subsets[v].parent = v;
subsets[v].rank = 0;
}
// Iterate through all edges of the graph, perform union-find
for (int e = 0; e < graph->E; e++) {
int x = find(subsets, edges[e].src);
int y = find(subsets, edges[e].dest);
if (x != y) {
unionSets(subsets, x, y);
}
}
// Count the number of unique parents in subsets
int count = 0;
for (int v = 0; v < V; v++) {
if (subsets[v].parent == v) {
count++;
}
}
free(subsets);
return count;
}
int main() {
// Example graph
int V = 6; // Number of vertices
int E = 4; // Number of edges
struct Graph* graph = createGraph(V, E);
// Add edges to the graph
graph->edges[0].src = 0;
graph->edges[0].dest = 1;
graph->edges[1].src = 2;
graph->edges[1].dest = 3;
graph->edges[2].src = 4;
graph->edges[2].dest = 5;
graph->edges[3].src = 3;
graph->edges[3].dest = 4;
int components = countComponents(graph);
printf("Number of connected components: %d\n", components);
free(graph->edges);
free(graph);
return 0;
}