C++ Program to Implement Disjoint Set Data Structure

This C++ program implements the Disjoint Set data structure. It is a data structure that keeps track of a set of elements partitioned into a number of disjoint (nonoverlapping) subsets.

Here is the source code of the C++ program to display the sum of data subsets the data strucure has been partitioned in. This C++ program is successfully compiled and run on DevCpp, a C++ compiler. The program output is given below.

```
/*
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* C++ Program to Implement Disjoint Set Data Structure

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 */
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```
#include <iostream>
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#include <cstdio>
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#include <vector>
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#include <algorithm>
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using namespace std;
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#define INF 1000000000
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```
 
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typedef pair<int ,int> ii;
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typedef vector <int> vi;
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```
 
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vector <pair<int ,ii> > edges;
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vi pset;
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```
 
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void init(int N)
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{
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    pset.assign(N, 0);
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    for(int i = 0; i < N; i++)
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    {
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        pset[i] = i;
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    }
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}
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```
 
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int find_set(int i)
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{
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    if(pset[i] == i)
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    {
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        return pset[i];
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    }
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    return pset[i] = find_set(pset[i]);
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}
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bool issameset (int i, int j)
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{
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    return find_set(i) == find_set(j);
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}
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void joinset(int i, int j)
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{
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    pset[find_set(i)] = find_set(j);
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}
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int main()
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{
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    int n, m, a, b, dist, t;
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    cin>>t;
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    while(t--)
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    {
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        cin>>n>>m;
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        init(n);
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        edges.clear();
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        for (int i = 0; i < m; i++)
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        {
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            cin>>a>>b>>dist;
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            a--,b--;
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            ii tmp = make_pair(a, b);
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            edges.push_back(make_pair(dist, tmp));

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        }
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        sort(edges.rbegin(),edges.rend());

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        int sum = 0;
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        for(int i = 0; i < edges.size(); i++)

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        {
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            if (!issameset (edges[i].second.first, edges[i].second.second))

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            {
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               joinset(edges[i].second.first, edges[i].second.second);

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            }
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            else sum += edges[i].first;
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        }
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        cout<<sum;
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    }
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    cin>>t;
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    getch();
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}
```

Output
enter the number of sets to be  computed
1
enter the number of disjoint sets and the number of rows
2
3
enter the start and end vertices alongwith weight of edge
1
1
2
enter the start and end vertices alongwith weight of edge
1
1
3
enter the start and end vertices alongwith weight of edge
1
1
4
Sum is:9

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