Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

const (
	MAX_N      = 200
	MAX_WEIGHT = 2000
)

type Edge struct {
	start  int
	end    int
	weight int
}

type ShortestInfo struct {
	edges    []Edge
	shortest int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	shortestList := make([]ShortestInfo, n)
	for i := 1; i < n; i++ {
		shortestList[i] = ShortestInfo{edges: []Edge{}, shortest: MAX_N*MAX_WEIGHT + 1}
	}

	adjacentMatrix := make([][]int, n)
	for i := 0; i < n; i++ {
		adjacentMatrix[i] = make([]int, n)
		for j := 0; j < n; j++ {
			v, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjacentMatrix[i][j] = v
		}
	}

	mst([]int{1}, shortestList, adjacentMatrix)
	fmt.Println(calculateMinWeight(shortestList))
}

func calculateMinWeight(shortestList []ShortestInfo) int {
	visitedList := make([]bool, len(shortestList))
	visitedList[0] = true
	sumWeight := 0
	for !visitedAll(visitedList) {
		shortestInfo := shortestList[0]
		shortestList = shortestList[1:]
		edges := shortestInfo.edges
		for _, edge := range edges {
			if !visitedList[edge.end-1] {
				visitedList[edge.end-1] = true
				sumWeight += edge.weight
			}
		}
	}
	return sumWeight
}

func visitedAll(visitedList []bool) bool {
	for _, v := range visitedList {
		if !v {
			return false
		}
	}
	return true
}

func mst(nodeStack []int, shortestList []ShortestInfo, adjacentMatrix [][]int) {
	for len(nodeStack) > 0 {
		currentNode := nodeStack[0]
		nodeStack = nodeStack[1:]
		currentShortest := getShortest(currentNode, shortestList)
		adjacents := findAdjacents(currentNode, adjacentMatrix)
		for i := 0; i < len(adjacents); i++ {
			adj := adjacents[i]
			s := getShortest(adj.end, shortestList)
			if currentShortest.shortest+adj.weight < s.shortest || (currentShortest.shortest+adj.weight == s.shortest && len(currentShortest.edges)+1 > len(s.edges)) {
				setShortest(adj.end, adj, currentShortest, shortestList)
				nodeStack = append(nodeStack, adj.end)
			}
		}
	}
}

func getShortest(node int, shortestList []ShortestInfo) ShortestInfo {
	return shortestList[node-1]
}

func setShortest(node int, edge Edge, currentShortest ShortestInfo, shortestList []ShortestInfo) {
	newEdges := make([]Edge, len(currentShortest.edges)+1)
	for i := 0; i < len(newEdges)-1; i++ {
		newEdges[i] = currentShortest.edges[i]
	}
	newEdges[len(newEdges)-1] = edge
	shortestInfo := ShortestInfo{edges: newEdges, shortest: currentShortest.shortest + edge.weight}
	shortestList[node-1] = shortestInfo
}

func findAdjacents(currentNode int, adjacentMatrix [][]int) []Edge {
	adjacents := adjacentMatrix[currentNode-1]
	edges := []Edge{}
	for i, v := range adjacents {
		if v > 0 {
			edges = append(edges, Edge{start: currentNode, end: i + 1, weight: v})
		}
	}
	return edges
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <iostream>
#include <set>
#include <vector>
using namespace std;

int V, E, d[105][105], INF = 1e9;

int Prim() {
    int s = 0, c[105], n[105], ans = 0;
    set<int> U;
    for (int i = 1; i < V; i++) U.insert(i);
    bool p[10] = {};

    for (int i = 0; i < V; i++) {
        c[i] = d[s][i];
        n[i] = s;
    }
    vector<pair<int, int>> T;
    while (!U.empty()) {
        int mn = INF, w = -1;
        for (auto& i : U) {
            if (c[i] < mn) {
                mn = c[i];
                w = i;
            }
        }
        U.erase(w);
        T.emplace_back(w, n[w]);
        ans += d[w][n[w]];
        for (auto& i : U) {
            if (d[w][i] < c[i]) {
                c[i] = d[w][i];
                n[i] = w;
            }
        }
    }
    return ans;
}

int main() {
    cin >> V;
    for (int i = 0; i < V; i++) {
        for (int j = 0; j < V; j++) {
            cin >> d[i][j];
            if (d[i][j] == -1) d[i][j] = INF;
        }
    }

    cout << Prim() << endl;
}

C++: #include<iostream>
#include<queue>
#include <utility>
#include <vector>

#define MAX_NUM 10000

using namespace std;

int main(){
	priority_queue<int, vector<int>, less<int> >heap;
	int L,P,N,A[MAX_NUM],B[MAX_NUM],num=0;
	cin>>N>>L>>P;
	for(int i=0;i<N;i++){
		cin>>A[i];
	}
	for(int i=0;i<N;i++){
		cin>>B[i];
	}
	int i=0;
	while(L>P){
		while(A[i]<=P && i<N){
			heap.push(B[i]);
			i++;
		}
		if(heap.empty()==1){
			cout<<-1<<endl;
		}
		P+=heap.top();
		heap.pop();
		num++;
	}
	cout<<num<<endl;
	return 0;
}

C++: #include <iostream>
using namespace std;
static const int MAX =100;
static const int INFTY =(1<<21);
static const int WHITE =0;
static const int GRAY =1;
static const int BLACK =2;

int n, M[MAX][MAX];

int prim(){
  int u,minv;
  int d[MAX],p[MAX],color[MAX];

  for(int i=0;i<n;i++){
    d[i]=INFTY;
    p[i]=-1;
    color[i]=WHITE;
  }
  d[0]=0;

  while(1){
    minv=INFTY;
    u=-1;
    for(int i=0;i<n;i++){
      if(minv>d[i] && color[i] !=BLACK){
        u=i;
        minv=d[i];
      }
    }
    if(u==-1)break;
    color[u]=BLACK;
    for(int v=0;v<n;v++){
      if(color != BLACK && M[u][v]!=INFTY){
        if(d[v]>M[u][v]){
          d[v]=M[u][v];
          p[v]=u;
          color[v]=GRAY;
        }
      }
    }
  }
  int sum=0;
  for(int i=0;i<n;i++){
    if(p[i]!=-1)sum+=M[i][p[i]];
  }
  return sum;
}

int main(){
  cin >> n;

  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    int e; cin >> e;
    M[i][j]= (e==-1)? INFTY:e;
    }
  }

  cout << prim() << endl;
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;

#define MAX_N 100
#define MAX_EDGE_COST 20000
int Graph[MAX_N+1][MAX_N+1];
int n;

int prim(int initial_vertex) {
  bool visited[n+1];
  for(int i=1;i<=n;i++) visited[i] = false;
  vector<int> vertexes;
  vertexes.push_back(initial_vertex);
  visited[initial_vertex] = true;
  int total_edge_cost = 0;
  while(vertexes.size() <= n) {
    // find minimum edge cost in vertexes
    int minimum_edge_cost = MAX_EDGE_COST;
    int next_v;
    for(int i=0;i<vertexes.size();i++) {
      int v = vertexes[i];
      for(int j=1;j<=n;j++) {
        if(!visited[j]) {
          if(Graph[v][j] != -1) {
            if(Graph[v][j] < minimum_edge_cost) {
              minimum_edge_cost = Graph[v][j];
              next_v = j;
            }
          }
        }
      }
    }
    vertexes.push_back(next_v);
    total_edge_cost += minimum_edge_cost;
  }
  return total_edge_cost;
}

int main() {
  scanf("%d",&n);
  for(int i=1;i<=n;i++) {
    for(int j=1;j<=n;j++) {
      scanf("%d ",&Graph[i][j]);
    }
  }
  printf("%d\n",prim(1));
}

C++: #include <iostream>
using namespace std;
static const int MAX=101;
static const int INFTY=(1<<21);
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;

int n,M[MAX][MAX];

int prim(){
    int u,minv;
    int d[MAX],p[MAX],color[MAX];
    for(int i=0;i<n;i++){
        d[i]=INFTY;
        p[i]=-1;
        color[i]=WHITE;
    }
    
    d[0]=0;
    
    while(1){
        minv=INFTY;
        u=-1;
        for(int i=0;i<n;i++){
            if(minv>d[i] && color[i]!=BLACK){
                u=i;
                minv=d[i];
            }
        }
        if(u==-1) break;
        color[u] = BLACK;
        for(int i=0;i<n;i++){
            if(color[i]!=BLACK && M[u][i]!=INFTY){
                if(d[i]>M[u][i]){
                    d[i]=M[u][i];
                    p[i]=u;
                    color[i]=GRAY;
                }
            }
        }
    }
    int sum=0;
    for(int i=0;i<n;i++){
        if(p[i]!=-1) sum += M[i][p[i]];
    }
    
    return sum;
}

int main(){
    cin >> n;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            cin >> M[i][j];
            if(M[i][j]==-1) M[i][j]=INFTY;
        }
    }
    
    cout << prim() << endl;
    
    return 0;
}