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Graph-Minimum spanning tree-Kruskal Algorithm.cpp
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Graph-Minimum spanning tree-Kruskal Algorithm.cpp
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#include <cmath>
#include<ext/pb_ds/priority_queue.hpp>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int find_parent(int parent[],int i)
{
if(parent[i]==-1)
return i;
return find_parent(parent,parent[i]);
}
void union_of_edge(int parent[],int x,int y)
{
int xx=find_parent(parent,x);
int yy=find_parent(parent,y);
if(xx!=yy)
parent[xx]=yy;
}
struct edge
{
int u,v,w;
};
int main() {
int n,m,u,v,w;
//n # of vertices,m # of edges
//4 6 <-n,m
// 1 2 5 <- vertices with weight u,v,w
// 1 3 3
// 4 1 6
// 2 4 7
// 3 2 4
// 3 4 5
cin>>n>>m;
priority_queue<pair<int,pair<int,int>>>q;
for(int i=0;i<m;i++)
{
cin>>u>>v>>w;
u--;
v--;
q.push({-w,{u,v}});
}
edge sorted[m];
for(int i=0;i<m;i++)
{
pair<int,pair<int,int>> temp = q.top();
sorted[i].w=(-1*temp.first);
sorted[i].u=temp.second.first;
sorted[i].v=temp.second.second;
q.pop();
}
vector<int> weight;
int parent[n];
for(int j=0;j<n;j++)
parent[j]=-1;
for(int i=0;i<m;i++)
{
int x=find_parent(parent,sorted[i].u);
int y=find_parent(parent,sorted[i].v);
if(x!=y)
{
weight.push_back(sorted[i].w);
union_of_edge(parent,x,y);
}
}
int sum=0;
for(int i=0;i<weight.size();i++)
{
sum+=weight[i];
}
cout<<"Cost of Minimum spanning tree of Graph:::"<<sum;
return 0;
}