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| 1 | + |
| 2 | +#include <stdio.h> |
| 3 | +#include <limits.h> |
| 4 | +#include<stdbool.h> |
| 5 | + |
| 6 | +#define V 5 |
| 7 | + |
| 8 | +int minKey(int key[], bool mstSet[]) |
| 9 | +{ |
| 10 | + |
| 11 | +int min = INT_MAX, min_index; |
| 12 | + |
| 13 | +for (int v = 0; v < V; v++) |
| 14 | + if (mstSet[v] == false && key[v] < min) |
| 15 | + min = key[v], min_index = v; |
| 16 | + |
| 17 | +return min_index; |
| 18 | +} |
| 19 | + |
| 20 | + |
| 21 | +int printMST(int parent[], int n, int graph[V][V]) |
| 22 | +{ |
| 23 | +printf("Edge \tWeight\n"); |
| 24 | +for (int i = 1; i < V; i++) |
| 25 | + printf("%d - %d \t%d \n", parent[i], i, graph[i][parent[i]]); |
| 26 | +} |
| 27 | + |
| 28 | +void primMST(int graph[V][V]) |
| 29 | +{ |
| 30 | + |
| 31 | + int parent[V]; |
| 32 | + |
| 33 | + int key[V]; |
| 34 | + |
| 35 | + bool mstSet[V]; |
| 36 | + |
| 37 | + for (int i = 0; i < V; i++) |
| 38 | + key[i] = INT_MAX, mstSet[i] = false; |
| 39 | + |
| 40 | + |
| 41 | + key[0] = 0; |
| 42 | + parent[0] = -1; // First node is always root of MST |
| 43 | + |
| 44 | + |
| 45 | + for (int count = 0; count < V-1; count++) |
| 46 | + { |
| 47 | + |
| 48 | + int u = minKey(key, mstSet); |
| 49 | + |
| 50 | + |
| 51 | + mstSet[u] = true; |
| 52 | + |
| 53 | + for (int v = 0; v < V; v++) |
| 54 | + |
| 55 | + if (graph[u][v] && mstSet[v] == false && graph[u][v] < key[v]) |
| 56 | + parent[v] = u, key[v] = graph[u][v]; |
| 57 | + } |
| 58 | + |
| 59 | + |
| 60 | + printMST(parent, V, graph); |
| 61 | +} |
| 62 | + |
| 63 | + |
| 64 | + |
| 65 | +int main() |
| 66 | +{ |
| 67 | +/* Let us create the following graph |
| 68 | + 2 3 |
| 69 | + (0)--(1)--(2) |
| 70 | + | / \ | |
| 71 | + 6| 8/ \5 |7 |
| 72 | + | / \ | |
| 73 | + (3)-------(4) |
| 74 | + 9 */ |
| 75 | +int graph[V][V] = {{0, 2, 0, 6, 0}, |
| 76 | + {2, 0, 3, 8, 5}, |
| 77 | + {0, 3, 0, 0, 7}, |
| 78 | + {6, 8, 0, 0, 9}, |
| 79 | + {0, 5, 7, 9, 0}}; |
| 80 | + |
| 81 | + |
| 82 | + primMST(graph); |
| 83 | + |
| 84 | + return 0; |
| 85 | +} |
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