Implementing Prim's Algorithm-Logical Error - algorithm

Question

I have been implementing prim's algorithm in c++, but I am not able to figure out why my algorithm is giving the wrong output.
Input Format: The first line has number of Test cases T.For each test case, Number of vertices and Number of edges are given in next line.For the Number of edges, each line consists of 3 numbers a,b,w where there is an undirected,weighted edge between vertices a and b with weight w.
Below is my code :
#include <bits/stdc++.h>
using namespace std;
int spanningTree(int V,int E,vector<vector<int> > graph);
// Driver code
int main()
{
int t;
cin>>t;
while(t--)
{
int V,E;
cin>>V>>E;
vector< vector<int> > graph(V,vector<int>(V,INT_MAX));
while(E--)
{
int u,v,w;
cin>>u>>v>>w;
u--,v--;
graph[u][v] = w;
graph[v][u] = w;
}
cout<<spanningTree(V,E,graph)<<endl;
}
return 0;
}
/*This is a function problem.You only need to complete the function given below*/
// Function to construct and print MST for
// a graph represented using adjacency
// matrix representation, with V vertices.
// graph[i][j] = weight if edge exits else INT_MAX
#include <limits.h>
int *parent;
bool *spt;
int *distance1;
int getMinVertex(int distance1[],bool spt[],int V)
{
int min_weight=INT_MAX,min_vertex=-1;
for(int i=0;i<V;i++)
{
if(!spt[i] && distance1[i]<min_weight)
min_weight=distance1[i],min_vertex=i;
}
cout<<"Min vertex : "<<min_vertex<<endl;
return min_vertex;
}
int spanningTree(int V,int E,vector<vector<int> > graph)
{
// code here
parent=new int[V];
spt=new bool[V];
distance1=new int[V];
for(int i=0;i<V;i++)
parent[i]=-1,spt[i]=false,distance1[i]=INT_MAX;
distance1[0]=0;
parent[0]=-1;
//spt[0]=true;
int current_vertex=getMinVertex(distance1,spt,V);
int mst_weight=0;
while(current_vertex!=-1)
{ cout<<"Visiting : "<<current_vertex<<endl;
for(int i=0;i<V;i++)
{
if(i!=current_vertex) //ignore self-loop
{
int neighbour_weight=graph[current_vertex][i];
if(!spt[i]&&neighbour_weight!=INT_MAX&&distance1[i]>graph[current_vertex][i])
{
distance1[i]=graph[current_vertex][i];
parent[i]=current_vertex;
}
}
}
mst_weight+=distance1[current_vertex];
spt[current_vertex]=true;
current_vertex=getMinVertex(distance1,spt,V);
cout<<"\nDistance array : \n";
for(int i=0;i<V;i++)
cout<<"dist["<<i<<"]:"<<distance1[i]<<" ";
cout<<endl;
cout<<"\nParent Array\n";
for(int i=0;i<V;i++)
cout<<"Parent["<<i<<"]:"<<parent[i]<<" ";
cout<<"\n\n";
} //end of while loop.
delete [] parent;
delete [] spt;
delete [] distance1;
//cout<<mst_weight<<endl;
return mst_weight;
}
Array spt[] consists of set of vertices already included in the set of minimum spanning tree.distance1[] array holds the distance values.Array parent[] is used to keep track of MST tree being formed.
Below is the code output for input:
2
3 2
1 2 3 1 3 3
4 3
1 3 5 1 4 6 2 3 7
Output:
Min vertex : 0
Visiting : 0
Min vertex : 2
Distance array :
dist[0]:0 dist[1]:5 dist[2]:1
Parent Array
Parent[0]:-1 Parent[1]:0 Parent[2]:0
Visiting : 2
Min vertex : 1
Distance array :
dist[0]:0 dist[1]:3 dist[2]:1
Parent Array
Parent[0]:-1 Parent[1]:2 Parent[2]:0
Visiting : 1
Min vertex : -1
Distance array :
dist[0]:0 dist[1]:3 dist[2]:1
Parent Array
Parent[0]:-1 Parent[1]:2 Parent[2]:0
4
Min vertex : 0
Visiting : 0
Min vertex : 1
Distance array :
dist[0]:0 dist[1]:5
Parent Array
Parent[0]:-1 Parent[1]:0
Visiting : 1
Min vertex : -1
Distance array :
dist[0]:0 dist[1]:5
Parent Array
Parent[0]:-1 Parent[1]:0
5
I am completely unable to make out what is going wrong with my code.Can someone please help.