TheAlgorithms-C-Plus-Plus/greedy_algorithms/Prims Minimum Spanning Tree.cpp

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#include <iostream>
using namespace std;
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#define V 4
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#define INFINITY 99999
int graph[V][V] = {
{0, 5, 1, 2},
{5, 0, 3, 3},
{1, 3, 0, 4},
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{2, 3, 4, 0}};
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struct mst
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{
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bool visited;
int key;
int near;
};
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mst MST_Array[V];
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void initilize()
{
for (int i = 0; i < V; i++)
{
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MST_Array[i].visited = false;
MST_Array[i].key = INFINITY; // considering INFINITY as inifinity
MST_Array[i].near = i;
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}
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MST_Array[0].key = 0;
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}
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void updateNear()
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{
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for (int v = 0; v < V; v++)
{
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int min = INFINITY;
int minIndex = 0;
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for (int i = 0; i < V; i++)
{
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if (MST_Array[i].key < min && MST_Array[i].visited == false && MST_Array[i].key != INFINITY)
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{
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min = MST_Array[i].key;
minIndex = i;
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}
}
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MST_Array[minIndex].visited = true;
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for (int i = 0; i < V; i++)
{
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if (graph[minIndex][i] != 0 && graph[minIndex][i] < INFINITY)
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{
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if (graph[minIndex][i] < MST_Array[i].key)
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{
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MST_Array[i].key = graph[minIndex][i];
MST_Array[i].near = minIndex;
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}
}
}
}
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}
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void show()
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{
for (int i = 0; i < V; i++)
{
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cout << i << " - " << MST_Array[i].near << "\t" << graph[i][MST_Array[i].near] << "\n";
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}
}
int main()
{
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initilize();
updateNear();
show();
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return 0;
}