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| 1 | +#include <cstdio> |
| 2 | +#include <climits> |
| 3 | + |
| 4 | +// Number of vertices in the graph |
| 5 | +#define V 9 |
| 6 | +int minDistance(int dist[], bool sptSet[]) |
| 7 | +{ |
| 8 | + // Initialize min value |
| 9 | + int min = INT_MAX, min_index; |
| 10 | + |
| 11 | + for (int v = 0; v < V; v++) |
| 12 | + if (sptSet[v] == false && dist[v] <= min) |
| 13 | + min = dist[v], min_index = v; |
| 14 | + |
| 15 | + return min_index; |
| 16 | +} |
| 17 | + |
| 18 | +void printSolution(int dist[], int n) |
| 19 | +{ |
| 20 | + printf("Vertex Distance from Source\n"); |
| 21 | + for (int i = 0; i < V; i++) |
| 22 | + printf("%d tt %d\n", i, dist[i]); |
| 23 | +} |
| 24 | + |
| 25 | +void dijkstra(int graph[V][V], int src) |
| 26 | +{ |
| 27 | + int dist[V]; // The output array. dist[i] will hold the shortest |
| 28 | + // distance from src to i |
| 29 | + |
| 30 | + bool sptSet[V]; // sptSet[i] will true if vertex i is included in shortest |
| 31 | + // path tree or shortest distance from src to i is finalized |
| 32 | + |
| 33 | + // Initialize all distances as INFINITE and stpSet[] as false |
| 34 | + for (int i = 0; i < V; i++) |
| 35 | + dist[i] = INT_MAX, sptSet[i] = false; |
| 36 | + |
| 37 | + // Distance of source vertex from itself is always 0 |
| 38 | + dist[src] = 0; |
| 39 | + |
| 40 | + // Find shortest path for all vertices |
| 41 | + for (int count = 0; count < V-1; count++) |
| 42 | + { |
| 43 | + // Pick the minimum distance vertex from the set of vertices not |
| 44 | + // yet processed. u is always equal to src in the first iteration. |
| 45 | + int u = minDistance(dist, sptSet); |
| 46 | + |
| 47 | + // Mark the picked vertex as processed |
| 48 | + sptSet[u] = true; |
| 49 | + |
| 50 | + // Update dist value of the adjacent vertices of the picked vertex. |
| 51 | + for (int v = 0; v < V; v++) |
| 52 | + |
| 53 | + // Update dist[v] only if is not in sptSet, there is an edge from |
| 54 | + // u to v, and total weight of path from src to v through u is |
| 55 | + // smaller than current value of dist[v] |
| 56 | + if (!sptSet[v] && graph[u][v] && dist[u] != INT_MAX |
| 57 | + && dist[u]+graph[u][v] < dist[v]) |
| 58 | + dist[v] = dist[u] + graph[u][v]; |
| 59 | + } |
| 60 | + printSolution(dist, V); |
| 61 | +} |
| 62 | + |
| 63 | +int main() |
| 64 | +{ |
| 65 | + /* Sample graph */ |
| 66 | + int graph[V][V] = {{0, 4, 0, 0, 0, 0, 0, 8, 0}, |
| 67 | + {4, 0, 8, 0, 0, 0, 0, 11, 0}, |
| 68 | + {0, 8, 0, 7, 0, 4, 0, 0, 2}, |
| 69 | + {0, 0, 7, 0, 9, 14, 0, 0, 0}, |
| 70 | + {0, 0, 0, 9, 0, 10, 0, 0, 0}, |
| 71 | + {0, 0, 4, 14, 10, 0, 2, 0, 0}, |
| 72 | + {0, 0, 0, 0, 0, 2, 0, 1, 6}, |
| 73 | + {8, 11, 0, 0, 0, 0, 1, 0, 7}, |
| 74 | + {0, 0, 2, 0, 0, 0, 6, 7, 0} |
| 75 | + }; |
| 76 | + dijkstra(graph, 0); |
| 77 | + return 0; |
| 78 | +} |
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