Prims Algorithm using matrix

#include<bits/stdc++.h>
using namespace std;

int adj[1000][1000];
class Node{
public:
    int v,cost;
    Node()
    {

    }
    Node(int vertex,int costt)
    {
        v= vertex;
        cost = costt;
    }

};
bool operator<(Node a,Node b)
{
    return a.cost>b.cost;
}
class Prims{
        int vertex,edge,u,v,weight,i,j,ans = 0;
        bool visited[100] = {false};
public:
    void input()
    {
        cin>>vertex>>edge;
        for(int i=1; i<=edge;i++)
        {
            cin>>u>>v>>weight;
            adj[u][v] = weight;
            adj[v][u] = weight;
        }
    }
    void solution()
    {
        priority_queue<Node>pq;
        pq.push(Node(0,0));
        int parent[100]={0};
        while(!pq.empty())
        {
            Node temp = pq.top();
            pq.pop();
            if(visited[temp.v] == 1) continue;
            cout<<parent[temp.v]<<" "<<temp.v<<" "<<temp.cost<<endl;
            //parent = temp.v;
            ans +=temp.cost;
            visited[temp.v] =1;
            for(i = 0;i<vertex;i++)
            {
                /// for loop not create
                if(visited[i] == 1)
                {
                    continue;
                }
                /// skip some vertex that are not adjacent
                if(adj[temp.v][i] !=0)
                {
                    pq.push(Node(i,adj[temp.v][i]));
                    parent[i]= temp.v;
                    //cout<<i<<" "<<adj[temp.v][i]<<endl;
                }
            }
        }
        cout<<endl<<"Minimum cost is "<<ans<<endl;
    }
};
int main()
{
    freopen("input.txt","r",stdin);

    Prims p;
    p.input();
    p.solution();
}