Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

C++: #include<stdio.h>

#define MAX 1000
#define INFINITY 300000

int n;
int M[MAX][MAX], color[MAX], d[MAX], p[MAX];

enum Color {
    WHITE,
    GRAY,
    BLACK
};

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

    while (true) {
        int min = INFINITY;
        int target = -1;
        for (int i = 0; i < n; ++i) {
            if (d[i] < min && color[i] != BLACK) {
                min = d[i];
                target = i;
            }
        }
        if (target == -1) break;

        color[target] = BLACK;

        for (int v = 0; v < n; ++v) {
            if (color[v] != BLACK && M[target][v] != -1) {
                if(M[target][v] + d[target] < d[v]) {
                    d[v] = d[target] + M[target][v];
                    p[v] = target;
                    color[v] = GRAY;
                }
            }
        }
    }

    for (int i = 0; i < n; ++i) {
        printf("%d %d\n", i, d[i]);
    }
}

int main() {
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            M[i][j] = -1;
        }
    }
    for (int i = 0; i < n; ++i) {
        int id, k;
        scanf("%d %d", &id, &k);
        for (int j = 0; j < k; ++j) {
            int t;
            scanf("%d", &t);
            scanf("%d", &M[id][t]);
        }
    }
    dijkstra();
    return 0;
}

C++: #include <bits/stdc++.h>
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 << " " << 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();

};

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

using namespace std;
static const int MAX=10000;
static const int INFTY = (1<<21);

vector< pair<int,int> >M[MAX]; //?????\??¨
priority_queue< pair<int,int> > PQ; //????????§??????, first???d[i], second???i??? ?????¨??¶?????????first???????????°
bool visited[MAX]; //???????¢??????????
int d[MAX]; //?????????????????¬

void dijkstra_implementsPQ(int n)
{
    //init
    for(int i=0;i<n;i++)
    {
        d[i]=INFTY;
        visited[i]=false;
    }
    //select node 0
    d[0]=0;
    PQ.push(make_pair(0,0));

    while(!PQ.empty())
    {
        //currently the top of PQ is the shortest one
        pair<int,int> temp=PQ.top();PQ.pop();
        int u=temp.second;

        visited[u]=true;
        if(d[u]<temp.first*(-1)) continue;

        //update
        for(int j=0;j<M[u].size();j++)
        {
            int v=M[u][j].first;
            if(visited[v]==true) continue;
            //else try updating
            if(d[v]>d[u]+M[u][j].second)
            {
                d[v]=d[u]+M[u][j].second;
                PQ.push(make_pair(d[v]*(-1),v));
            }
        }
    }
    //print
    for(int i=0;i<n;i++)  cout<<i<<' '<<(d[i]==INFTY?-1:d[i])<<endl;

}
int main()
{
    int n;
    cin>>n;

    for(int i=0;i<n;i++)
    {
        int u,k;
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            int v,d;
            cin>>v>>d;
            M[u].push_back(make_pair(v,d));
        }
    }

    dijkstra_implementsPQ(n);
}

C++: #include<bits/stdc++.h>

using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

typedef long long ll;
typedef pair<int, int> P;

#define MAX 100005
#define INF INT_MAX

struct Edge {
    int to;
    int cost;
};

int main(int, char**)
{
    int n;
    cin >> n;

    vector< vector<Edge> > G(n);
    rep(i,n) {
        int u, k;
        cin >> u >> k;
        rep(j,k) {
            int v, c;
            cin >> v >> c;
            G[u].push_back({v, c});
        }
    }
    priority_queue<P> q;
    vector<int> d(n, INF);
    d[0] = 0;
    q.push({0, 0});
    while (!q.empty()) {
        int v, c;
        tie(c,v) = q.top(); q.pop();
        if (d[v] < c) continue;
        for (auto e : G[v]) {
            if (d[e.to] <= d[v] + e.cost) continue;
            d[e.to] = d[v] + e.cost;
            q.push({d[e.to], e.to});
        }
    }
    rep(i,n) cout << i << " " << d[i] << endl;

    return 0;
}