Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const (
	INFTY = 1 << 21
	NIL   = -1
)

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph [][]int

func (g *Graph) dikstra(n int) string {
	var (
		u, minv = 0, 0
	)

	d := make([]int, n)
	color := make([]int, n)

	for i := 0; i < n; i++ {
		d[i] = INFTY
		color[i] = WHITE
	}
	d[0] = 0
	color[0] = GRAY

	for {
		minv = INFTY
		u = -1
		for 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 v := 0; v < n; v++ {
			if color[v] != BLACK && (*g)[u][v] != INFTY {
				if d[v] > d[u]+(*g)[u][v] {
					d[v] = d[u] + (*g)[u][v]
					color[v] = GRAY
				}
			}
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d ", i))
		if d[i] == INFTY {
			out.WriteString(fmt.Sprintf("%d\n", -1))
			continue
		}
		out.WriteString(fmt.Sprintf("%d\n", d[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	g := make(Graph, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for j := 0; j < n; j++ {
			g[i][j] = INFTY
		}
	}

	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())

		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			sc.Scan()
			c, _ := strconv.Atoi(sc.Text())

			g[u][v] = c
		}
	}

	return g.dikstra(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include <bits/stdc++.h>
using namespace std;
long long INF = 1000000000000000;
vector<long long> bellman_ford(vector<vector<pair<int, int>>> &E, int s){
    int V = E.size();
    vector<long long> d(V, INF);
    d[s] = 0;
    while (1){
        bool update = false;
        for (int i = 0; i < V; i++){
            for (int j = 0; j < E[i].size(); j++){
                int c = E[i][j].first;
                int v = E[i][j].second;
                if (d[v] > d[i] + c && d[i] != INF){
                    d[v] = d[i] + c;
                    update = true;
                }
            }
        }
        if (!update){
            break;
        }
    }
    return d;
}
int main(){
    int n;
    cin >> n;
    vector<vector<pair<int, int>>> E(n);
    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[i].push_back(make_pair(c, v));
        }
    }
    vector<long long> d = bellman_ford(E, 0);
    for (int i = 0; i < n; i++){
        cout << i << ' ' << d[i] << endl;
    }
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int, int>;

struct edge {int to, cost;};

int main(void){
    int n;
    cin >> n;
    vector<edge> d[n];
    rep(i, n){
        int u, k;
        cin >> u >> k;
        rep(j, k){
            int v, c;
            cin >> v >> c;
            d[u].push_back({v, c});
        }
    }
    vector<int> v(n);
    fill(v.begin(), v.end(), INT_MAX);
    priority_queue<P,vector<P>, greater<P>> q;
    q.push({0, 0});
    while(!q.empty()){
        P p = q.top(); q.pop();
        int g = p.second;
        if(v[g] < p.first) continue;
        v[g] = p.first;
        for(auto x : d[g]){
            if(v[x.to] > v[g] + x.cost)
                q.push({v[g] + x.cost, x.to});
        }
    }
    rep(i, n) cout << i << ' ' << v[i] << endl;
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int n;
vector< vector<int> > G;
vector<int> color, d, p;

void Dijsktra() {
  color.resize(n), d.resize(n, 1000000000), p.resize(n, -1);
  d[0] = 0;

  while (true) {
    int min_cost = 1000000000, u;
    for (int i = 0; i < n; i++) if (color[i] != 2 && d[i] < min_cost) min_cost = d[i], u = i;
    if (min_cost == 1000000000) break;
    color[u] = 2;
    for (int v = 0; v < n; v++) {
      if (color[v] != 2 && G[u][v] != -1)
        if (d[u] + G[u][v] < d[v]) d[v] = d[u] + G[u][v], p[v] = u, color[v] = 1;
    }
  }
}

int main() {
  cin >> n;
  G.resize(n, vector<int>(n, -1));
  for (int i = 0; i < n; i++) {
    int u, k;
    cin >> u >> k;
    for (int i = 0; i < k; i++) {
      int v, c;
      cin >> v >> c;
      G[u][v] = c;
    }
  }

  Dijsktra();

  for (int i = 0; i < n; i++) cout << i << " " << d[i] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef long long ll;

struct Edge {
    ll t,w;
};

struct State {
    ll v;
    ll score;
    bool operator < (const State& tgt) const {
	return score > tgt.score;
    }
};

vector<ll> dijkstra(vector<vector<Edge>>& G, const int start) {
    const ll V = G.size();

    vector<ll>res(V,INT_MAX);
    priority_queue<State> q;
    q.push( State{0,0} );
    while( q.size() ) {
	State s = q.top(); q.pop();
	if( res[s.v] != INT_MAX ) continue;
	res[s.v] = s.score;
	for(auto& e : G[s.v]) {
	    if( res[e.t] != INT_MAX ) continue;
	    q.push( State{e.t, s.score + e.w} );
	}
    }
    return res;
}


int main () {

    ll V; cin >> V;
    vector<vector<Edge>> G(V);
    for(int i=0; i<V; i++) {
	ll u,k; cin >> u >> k;
	for(int j=0; j<k; j++) {
	    ll v,w; cin >> v >> w;
	    G[i].push_back( Edge{v,w} );
	}
    }
    vector<ll> res = dijkstra(G,0);
    for(int i=0; i<V; i++) {
	cout << V << " " << res[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 << " " << (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;
		}
	}

	dijkstra();

	return 0;
}

C++: #include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
#include <cstring>
#include <deque>
#include <iomanip>
#include <limits>
#include <fstream>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
#define CLR(mat) memset(mat, 0, sizeof(mat))
typedef long long ll;
const int inf = 1e9;
// ダイクストラO(elogv)
struct edge{
  int to, cost;
  edge(int t, int c) {
    to = t, cost = c;
  }
};
typedef pair<int, int> P;
int N;
vector<edge> G[111];
int d[111];
void dijkstra(int s){
  priority_queue<P, vector<P>, greater<P> >que;
  FOR(i,1,N+1) d[i] = inf;
  d[s] = 0;
  que.push(P(0, s));
  while(!que.empty()){
    P p = que.top(); que.pop();
    int v = p.second;
    if(d[v] < p.first) continue;
    for(auto &e : G[v]){
      if(d[e.to] > d[v] + e.cost){
        d[e.to] = d[v] + e.cost;
        que.push(P(d[e.to], e.to));
      }
    }
  }
}
int main()
{
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin>>N;
  FOR(i,0,N){
    int u, k;
    cin >> u >> k;
    FOR(j,0,k){
      int v, c;
      cin >> v >> c;
      G[u].push_back(edge(v, c));
    }
  }
  dijkstra(0);
  FOR(i,0,N){
    cout << i << " " << d[i] << endl;
  }
}