diff --git a/Dynamic Programming/BellmanFord.cpp b/Dynamic Programming/BellmanFord.cpp new file mode 100644 index 0000000..a8e423d --- /dev/null +++ b/Dynamic Programming/BellmanFord.cpp @@ -0,0 +1,117 @@ +#include + +struct Edge { + int src, dest, weight; +}; + +struct Graph { + + int V, E; + + + struct Edge* edge; +}; + + +struct Graph* createGraph(int V, int E) +{ + struct Graph* graph = new Graph; + graph->V = V; + graph->E = E; + graph->edge = new Edge[E]; + return graph; +} + + +void printArr(int dist[], int n) +{ + printf("Vertex Distance from Source\n"); + for (int i = 0; i < n; ++i) + printf("%d \t\t %d\n", i, dist[i]); +} + +void BellmanFord(struct Graph* graph, int src) +{ + int V = graph->V; + int E = graph->E; + int dist[V]; + + + for (int i = 0; i < V; i++) + dist[i] = INT_MAX; + dist[src] = 0; + + + for (int i = 1; i <= V - 1; i++) { + for (int j = 0; j < E; j++) { + int u = graph->edge[j].src; + int v = graph->edge[j].dest; + int weight = graph->edge[j].weight; + if (dist[u] != INT_MAX && dist[u] + weight < dist[v]) + dist[v] = dist[u] + weight; + } + } + + + for (int i = 0; i < E; i++) { + int u = graph->edge[i].src; + int v = graph->edge[i].dest; + int weight = graph->edge[i].weight; + if (dist[u] != INT_MAX && dist[u] + weight < dist[v]) { + printf("Graph contains negative weight cycle"); + return; + } + } + + printArr(dist, V); + + return; +} + +int main() +{ + + int V = 5; + int E = 8; + struct Graph* graph = createGraph(V, E); + + + graph->edge[0].src = 0; + graph->edge[0].dest = 1; + graph->edge[0].weight = -1; + + + graph->edge[1].src = 0; + graph->edge[1].dest = 2; + graph->edge[1].weight = 4; + + + graph->edge[2].src = 1; + graph->edge[2].dest = 2; + graph->edge[2].weight = 3; + + graph->edge[3].src = 1; + graph->edge[3].dest = 3; + graph->edge[3].weight = 2; + + + graph->edge[4].src = 1; + graph->edge[4].dest = 4; + graph->edge[4].weight = 2; + + graph->edge[5].src = 3; + graph->edge[5].dest = 2; + graph->edge[5].weight = 5; + + graph->edge[6].src = 3; + graph->edge[6].dest = 1; + graph->edge[6].weight = 1; + + graph->edge[7].src = 4; + graph->edge[7].dest = 3; + graph->edge[7].weight = -3; + + BellmanFord(graph, 0); + + return 0; +}