Go: package main

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

const (
	white int = iota
	gray
	black
)

type node struct {
	id     int
	parent int
	edge   []int
	weight []int
	color  int
}

type graph struct {
	nodes    []node
	distance []int
}

var infty = 1 << 32
var null = -1

func constructgraph() *graph {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n := nextInt(sc)

	g := &graph{make([]node, n), make([]int, n)}

	for i := 0; i < n; i++ {
		id := nextInt(sc)
		edges := nextInt(sc)
		n := node{}
		n.id = id
		n.edge = make([]int, edges)
		n.weight = make([]int, edges)
		n.color = white
		for j := 0; j < edges; j++ {
			to := nextInt(sc)
			w := nextInt(sc)
			n.edge[j] = to
			n.weight[j] = w
		}
		g.nodes[id] = n
	}
	return g
}

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func (g *graph) preparedijkstra(s int) {
	for i := 0; i < len(g.nodes); i++ {
		g.nodes[i].color = white
		g.nodes[i].parent = null
		g.distance[i] = infty
	}
	g.distance[s] = 0
}

func (g *graph) dijkstra(s int) []int {
	g.preparedijkstra(s)

	for {
		var u int
		mincost := infty
		for i, d := range g.distance {
			if g.nodes[i].color != black && mincost > d {
				mincost = d
				u = i
			}
		}

		if mincost == infty {
			break
		}

		g.nodes[u].color = black

		for i, e := range g.nodes[u].edge {
			if g.nodes[e].color != black {
				if g.distance[e] > g.distance[u]+g.nodes[u].weight[i] {
					g.distance[e] = g.distance[u] + g.nodes[u].weight[i]
					g.nodes[e].parent = u
					g.nodes[e].color = gray
				}
			}
		}
	}
	return g.distance
}

func printShortestPath(d []int) {
	for i, v := range d {
		fmt.Printf("%d %d\n", i, v)
	}
}

func main() {
	g := constructgraph()
	d := g.dijkstra(0)
	printShortestPath(d)
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define loop(i,a,b) for(i=a;i<b;i++)
#define rloop(i,a,b) for(i=a;i>=b;i--)
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
const int inf=1000000001;
const ll INF=1e16;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;
static const int N=100;

int n;
vii m(N,vi(N));
vi d(N,inf);

void dijkstra();

int main(){
	int i,j;
	cin>>n;
	int u,k,v,c;
	loop(i,0,n){
		loop(j,0,n){
			m[i][j]=inf;
		}
	}
	loop(i,0,n){
		cin>>u>>k;
		loop(j,0,k){
			cin>>v>>c;
			m[u][v]=c;
		}
	}
	dijkstra();
	loop(i,0,n){
		cout<<i<<" "<<d[i]<<endl;
	}
}

void dijkstra(){
	int i;
	d[0]=0;
	vi color(n,WHITE);
	color[0]=BLACK;
	int u=0,v;
	while(1){
		int minv=inf;
		loop(i,0,n){
			if(color[i]!=BLACK){
				d[i]=min(d[i],d[u]+m[u][i]);
				if(minv>d[i]){
					minv=d[i];
					v=i;
				}
			}
		}
		if(minv==inf){
			break;
		}
		color[v]=BLACK;
		u=v;
	}
	
}

C++: #include <cstdio>
#include <vector>
#include <queue>
using namespace std;
const int MAX_V = 1e+4, INF = 1e+9;
struct edge {int to, cost;};
typedef pair<int, int> P; // 距離, 頂点
int n, d[MAX_V]; vector<edge> G[MAX_V];

void dijkstra(int s) {
  fill(d, d+n, INF); d[s] = 0;
  priority_queue<P, vector<P>, greater<P>> q;
  q.push(P(0, s));
  while(!q.empty()) {
    P p = q.top(); q.pop();
    int now = p.second;
    // 最短距離以外を無視
    if(d[now] < p.first) continue;
    for(int i = 0; i < G[now].size(); ++i) {
      edge e = G[now][i];
      if(d[e.to] > d[now] + e.cost) {
        d[e.to] = d[now] + e.cost;
        // とりあえず追加して、あとで最短距離以外を無視
        q.push(P(d[e.to], e.to));
      }
    }
  }
}
int main() {
  scanf("%d", &n);
  for(int i = 0, u, k; i < n; ++i) {
    scanf("%d %d", &u, &k);
    for(int j = 0, v, c; j < k; ++j) {
      scanf("%d %d", &v, &c);
      edge e = {v, c};
      G[u].push_back(e);
    }
  }
  dijkstra(0);
  for(int i = 0; i < n; ++i) {
    printf("%d %d\n", i, d[i]);
  }
}

C++: #include <iostream>
#include <vector>
#define INFTY 10000000
using namespace std;
int n,G[100][100];
int d[100],flag[100];
vector<int>path;
void dijkstra(){
    path.push_back(0);
    //int distance=0;
    int mini,min;
    while(path.size()<n){
        min=INFTY;
        int index=path.size()-1;
        //distance+=path[path.size()-1];
        for(int i=1;i<n;i++)
        {
            int temp=d[path[index]]+G[path[index]][i];
            if(d[i]>temp)
                d[i]=temp;
        }
        for(int i=1;i<n;i++)
        {
            if(flag[i])continue;
            if(d[i]<min)
            {
                min=d[i];
                mini=i;
            }
        }
        path.push_back(mini);
        flag[mini]=1;
        //distance+=path[path.size()-1];
    }
}
int main()
{
    int u,k,v,c;
    cin>>n;
    for(int i=0;i<n;i++)
    {
        d[i]=INFTY;
        flag[i]=0;
        for(int j=0;j<n;j++)
            G[i][j]=INFTY;
    }
    for(int i=0;i<n;i++)
    {
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            cin>>v>>c;
            G[u][v]=c;
        }
    }
    d[0]=0;
    dijkstra();
    for(int i=0;i<n;i++)
        cout<<i<<' '<<d[i]<<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];

void dijkstra(){
	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 << " ";
		if(d[i] == INFTY) cout << -1 << endl;
		else cout << 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;
		}
	}
	
	dijkstra();
	
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#define W 0
#define G 1
#define B 2
#define inf 1000000
#define MAX 100
#define NIL -1
using namespace std;

int n;
int A[MAX][MAX];

void Prim(){
    int color[MAX],d[MAX],p[MAX];
    int min,u;
    for(int i = 0; i < n; i++){
        color[i] = W;
        d[i] = inf;
        p[i] = NIL;
    }
    
    d[0] = 0;
    
    while(1){
        u = -1;
        min = inf;
        for(int i = 0; i < n; i++){
            if(d[i] < min && color[i] != B){
                u = i;
                min = d[i];
            }
        }
        
        if(u == -1) break;
            
        color[u] = B;
            
        for(int i = 0; i < n; i++){
            if(color[i] != B && A[u][i] != NIL){
                if(A[u][i] + d[u] < d[i]){
                    d[i] = A[u][i] + d[u];
                    color[i] = G;
                    p[i] = u;
                }
            }
        }
    }
    
    for (int i = 0; i < n; i++){
        printf("%d %d\n",i,d[i]);
    }
}

int main(){
    int u,k,c,v;
    scanf("%d",&n);
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            A[i][j] = inf;
        }
    }
    for(int i = 0; i < n; i++){
        scanf("%d %d", &u, &k);
        for(int j =0; j < k; j++){
            scanf("%d %d",&v,&c);
            A[i][v] = c;
        }
    }
    
    
    Prim();
    return 0;
}