Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

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 minv;
    int d[MAX], color[MAX];
    for (int i = 0; i < n; i++)
    {
        d[i] = INFTY;
        color[i] = WHITE;
    }
    d[0] = 0;
    color[0] = GRAY;
    while (1)
    {
        minv = INFTY;
        int 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[v] != BLACK && M[u][v] != INFTY)
            {
                if (d[v] > d[u] + M[u][v])
                {
                    d[v] = d[u] + M[u][v];
                    color[v] = GRAY;
                }
            }
        }
    }
    for (int i = 0; i < n; i++)
    {
        cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
    }
}
int main()
{
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            M[i][j] = INFTY;
        }
    }
    int k, c, u, v;
    for (int i = 0; i < n; i++)
    {
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            cin >> v >> c;
            M[u][v] = c;
        }
    }
    prim();
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long
int e[111][111],d[111];
int used[111];
signed main(){
  int n;
  cin>>n;
  int INF=1LL<<55LL;
  for(int i=0;i<n;i++)
    for(int j=0;j<n;j++)
      e[i][j]=INF;
  for(int i=0;i<n;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0;j<k;j++){
      int v,c;
      cin>>v>>c;
      e[u][v]=min(e[u][v],c);
    }
  }
  memset(used,0,sizeof(used));
  for(int i=0;i<n;i++) d[i]=INF;
  d[0]=0;
  while(1){
    int u=-1;
    for(int i=0;i<n;i++){
      if(used[i]) continue;
      if(d[i]==INF) continue;
      if(u<0||d[i]<d[u]) u=i;
    }
    if(u<0) break;
    used[u]=1;
    for(int i=0;i<n;i++){
      d[i]=min(d[i],d[u]+e[u][i]);
    }
  }
  for(int i=0;i<n;i++) cout<<i<<" "<<d[i]<<endl;
  return 0;
}

C++: #include<cstdio>
#include<iostream>
using namespace std;
int adj[101][101], d[101], visited[101];
int n, INFTY = (1<<30);
void dijkstra()
{
  for(int i=0; i<n; i++)
  {
    visited[i] = 0; d[i] = INFTY;
  }
  d[0] = 0;

  while(1)
  {
    int minc = INFTY, u=-1;
    for(int i=0; i<n; i++)
    {
      if(d[i] < minc && visited[i] == 0)
      {
        minc = d[i];
        u = i;
      }
    }
    if(minc == INFTY) break;
    visited[u] = 1;
    for(int i=0; i<n; i++)
    {
      if(adj[u][i] != -1 && visited[i]==0)
      {
        if(d[i] > d[u] + adj[u][i])
          d[i] = d[u] + adj[u][i];
      }
    }
  }
  for(int i=0; i<n; i++)
    printf("%d %d\n", i, d[i]);
}
int main()
{
  scanf("%d", &n);
  int u, k, c, v;
  for(int i=0; i<n; i++)
    for(int j=0; j<n; j++)
      adj[i][j] = -1;
  for(int i=0; i<n; i++)
  {
    scanf("%d%d", &u, &k);
    for(int j=0; j<k; j++)
    {
      scanf("%d%d", &v, &c);
      adj[u][v] = c;
    }
  }
  dijkstra();

  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;

void dijkstra(int n, int m[MAX][MAX]) {
    int minv;
    int d[MAX], color[MAX];

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

    d[0] = 0;
    color[0] = GRAY;

    while (true) {
        minv = INFTY;
        int 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[v] != BLACK && m[u][v] != INFTY) {
                if (d[v] > d[u] + m[u][v]) {
                    d[v] = d[u] + m[u][v];
                    color[v] = GRAY;
                }
            }
        }
    }

    for (int i = 0; i < n; i++) {
        cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
    }
}

int main() {
    int n, m[MAX][MAX];
    cin >> n;

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            m[i][j] = INFTY;
        }
    }

    int k, c, u, v;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            cin >> v >> c;
            m[u][v] = c;
        }
    }

    dijkstra(n, m);
}

C++: #include <bits/stdc++.h>
#define MOD 1000000007
#define INF 1<<30
#define rep(i,n) for(ll i=0; i<(n); i++)
#define REP(i,a,b) for(ll i=(a); i<(b); i++)
#define RREP(i,a,b) for(ll i=(a); i>=(b); i--)
#define all(x) (x).begin(),(x).end()
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll, ll> pl;
typedef vector<pair<ll, ll>> vpl;

vpl adj[10005];
ll n;

void dijkstra(){
    priority_queue<pl> pq;
    vl d(105,INF);
    int visit[105] = {};
    d[0] = 0;
    pq.push(make_pair(0,0));
    while(!pq.empty()){
        pl p = pq.top(); pq.pop();
        ll u = p.second;
        visit[u] = 1;
        if(d[u] < p.first * (-1)) continue;
        rep(i,adj[u].size()){
            ll v = adj[u][i].first;
            if(visit[v] == 1) continue;
            if(d[v] > d[u] + adj[u][i].second){
                d[v] = d[u] + adj[u][i].second;
                pq.push(make_pair(d[v]*(-1),v));
            }
        }
    }
    rep(i,n){
        cout << i << " " << ((d[i] == INF) ? -1 : d[i]) << "\n";
    }
}

int main(){
    cin >> n;
    ll k,c,u,v;
    rep(i,n){
        cin >> u >> k;
        rep(j,k){
            cin >> v >> c;
            adj[u].push_back(make_pair(v,c));
        }
    }

    dijkstra();

    return 0;
}