mirror of
https://github.com/TheAlgorithms/C
synced 2024-11-25 23:09:36 +03:00
105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
#include<stdio.h>
|
|
#include<stdlib.h>
|
|
#include<limits.h>
|
|
#include<string.h>
|
|
|
|
|
|
//Structure for storing a graph
|
|
struct Graph{
|
|
int vertexNum;
|
|
int** edges;
|
|
};
|
|
|
|
//Constructs a graph with V vertices and E edges
|
|
void createGraph(struct Graph* G,int V){
|
|
G->vertexNum = V;
|
|
G->edges =(int**) malloc(V * sizeof(int*));
|
|
for(int i=0; i<V; i++){
|
|
G->edges[i] = (int*) malloc(V * sizeof(int));
|
|
for(int j=0; j<V; j++)
|
|
G->edges[i][j] = INT_MAX;
|
|
G->edges[i][i] = 0;
|
|
}
|
|
}
|
|
|
|
//Adds the given edge to the graph
|
|
void addEdge(struct Graph* G, int src, int dst, int weight){
|
|
G->edges[src][dst] = weight;
|
|
}
|
|
|
|
|
|
//Utility function to print distances
|
|
void print(int dist[], int V){
|
|
printf("\nThe Distance matrix for Floyd - Warshall\n");
|
|
for(int i = 0; i < V; i++){
|
|
for(int j=0; j<V; j++){
|
|
|
|
if(dist[i*V+j] != INT_MAX)
|
|
printf("%d\t",dist[i*V+j]);
|
|
else
|
|
printf("INF\t");
|
|
}
|
|
printf("\n");
|
|
}
|
|
}
|
|
|
|
//The main function that finds the shortest path from a vertex
|
|
//to all other vertices using Floyd-Warshall Algorithm.
|
|
void FloydWarshall(struct Graph* graph){
|
|
int V = graph->vertexNum;
|
|
int dist[V][V];
|
|
|
|
//Initialise distance array
|
|
for(int i=0; i<V; i++)
|
|
for(int j=0; j<V; j++)
|
|
dist[i][j] = graph->edges[i][j];
|
|
|
|
|
|
//Calculate distances
|
|
for(int k=0; k<V; k++)
|
|
//Choose an intermediate vertex
|
|
|
|
for(int i=0; i<V; i++)
|
|
//Choose a source vertex for given intermediate
|
|
|
|
for(int j=0; j<V; j++)
|
|
//Choose a destination vertex for above source vertex
|
|
|
|
if(dist[i][k] != INT_MAX && dist[k][j] != INT_MAX && dist[i][k] + dist[k][j] < dist[i][j])
|
|
//If the distance through intermediate vertex is less than direct edge then update value in distance array
|
|
dist[i][j] = dist[i][k] + dist[k][j];
|
|
|
|
|
|
//Convert 2d array to 1d array for print
|
|
int dist1d[V*V];
|
|
for(int i=0; i<V; i++)
|
|
for(int j=0; j<V; j++)
|
|
dist1d[i*V+j] = dist[i][j];
|
|
|
|
print(dist1d,V);
|
|
}
|
|
|
|
//Driver Function
|
|
int main(){
|
|
int V,E;
|
|
int src,dst,weight;
|
|
struct Graph G;
|
|
printf("Enter number of vertices: ");
|
|
scanf("%d",&V);
|
|
printf("Enter number of edges: ");
|
|
scanf("%d",&E);
|
|
createGraph(&G,V);
|
|
for(int i=0; i<E; i++){
|
|
printf("\nEdge %d \nEnter source: ",i+1);
|
|
scanf("%d",&src);
|
|
printf("Enter destination: ");
|
|
scanf("%d",&dst);
|
|
printf("Enter weight: ");
|
|
scanf("%d",&weight);
|
|
addEdge(&G, src, dst, weight);
|
|
}
|
|
FloydWarshall(&G);
|
|
|
|
return 0;
|
|
}
|