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 <bits/stdc++.h>

#define rep(n) for(int i=0;i<n;i++)
#define repp(j, n) for(int j=0;j<n;j++)

using namespace std;

typedef long long ll;
typedef pair<ll, ll> Pll;
typedef pair<int, int> Pii;
struct edge{int from, to; ll cost;};

map<ll, ll> d;
priority_queue< Pll, vector<Pll>, greater<Pll> > que;
map<ll, vector<Pll> > edges;

void dijkstra(ll start){
    d[start] = 0;
    que.push(Pll(0, start));

    while(!que.empty()){
        Pll v = que.top(); que.pop();
        if(d.find(v.second) != d.end() && d[v.second] < v.first) continue;
        for(Pll e: edges[v.second]){
            if(d.find(e.first) == d.end() || d[e.first] > d[v.second] + e.second){
                d[e.first] = d[v.second] + e.second;
                que.push(Pll(d[e.first], e.first));
            }
        }
    }
}

int main(){
    std::ios::sync_with_stdio(0); cin.tie(0);
    int n;
    ll u, k, c, v;
    cin >> n;
    rep(n){
        cin >> u >> k;
        repp(j, k){
            cin >> v >> c;
            edges[u].emplace_back(v, c);
        }
    }

    dijkstra(0);
    repp(u, n) cout << u << " " << d[u] << endl;

}

C++: #include <iostream>

using namespace std;
static const int mx=107;
static const int inf=(1<<21);

int n,m[mx][mx];

void dijkstra()
{
	int minv;
	int d[mx],color[mx];
	
	for (int i=0;i<n;i++) {
		d[i]=inf;
		color[i]=0;
	}
	
	d[0]=0;
	color[0]=1;
	while (1) {
		minv=inf;
		int u=-1;
		for (int i=0;i<n;i++) {
			if(minv>d[i]&&color[i]!=2)
			{
				u=i;
				minv=d[i];
			}
		}
		if(u==-1)break;
		color[u]=2;
		for (int v=0;v<n;v++) {
			if(color[v]!=2&&m[u][v]!=inf)
			{
				if(d[v]>d[u]+m[u][v])
				{
					d[v]=d[u]+m[u][v];
					color[v]=1;
				}
			}
		}
	}
		for (int i=0;i<n;i++) 
			cout<<i<<" "<<(d[i]==inf?-1:d[i])<<endl;
}
int main(int argc, char *argv[]) {
	cin>>n;
	for (int i=0;i<n;i++) {
		for (int j=0;j<n;j++) {
			m[i][j]=inf;
		}
	}
	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<bits/stdc++.h>
using namespace std;
#define int long long
int e[111][111],d[111],used[111];
signed main(){
  int n;
  cin>>n;
  int INF=1LL<<55LL;
  fill((int*)e,(int*)(e+111),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 <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define all(vec) vec.begin(), vec.end()
#define END return 0
typedef int64_t ll;
const int mod7 = 1e9 + 7;
const int mod9 = 1e9 + 9;
const int inf = 1 << 30;
const ll INF = 1LL << 60;
template<typename T> T gcd(T a, T b) {return b ? gcd(b, a % b) : abs(a);}
template<typename T> T lcm(T a, T b) {return a / gcd(a, b) * b;}
template<typename T> bool chmax(T &a, T b) {if (a < b) {a = b; return true;} return false;}
template<typename T> bool chmin(T &a, T b) {if (a > b) {a = b; return true;} return false;}
template<typename A, size_t N, typename T> void Fill(A (&array)[N], const T &val) {fill((T*)array, (T*)(array+N), val);}

int n;
using P = pair<int, int>;
int l[100][100];
int d[100];

void dijkstra(int start) {
    fill(d, d + 100, inf);
    d[start] = 0;
    priority_queue<P, vector<P>, greater<P>> que;
    que.push({0, start});
    while(!que.empty()) {
        P p = que.top();
        que.pop();
        rep(i, n)
            if(chmin(d[i], p.first + l[p.second][i]))
                que.push({d[i], i});
    }
}

int main() {
    Fill(l, inf);
    cin >> n;
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        rep(i, k) {
            int v, c;
            cin >> v >> c;
            l[u][v] = c;
        }
    }
    dijkstra(0);
    rep(i, n) cout << i << ' ' << d[i] << endl;
}

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

using namespace std;

#define INF (10000001)

typedef pair<int, int> Edge;

int main()
{
    priority_queue<Edge,vector<Edge>,greater<Edge> > pq;
    vector<vector<Edge> > e;
    vector<int> d;
    Edge etemp;
    int n,u,k,v,c;
    cin >> n;
    e.resize(n);
    d.resize(n);
    for(int i=0; i<n; ++i) {
        cin >> u >> k;
        for(int j=0; j<k; ++j) {
            cin >> v >> c;
            e[u].push_back(Edge{c,v});
        }
        d[u]=INF;
    }

    d[0]=0;
    for(auto x : e[0]) {
        pq.push(x);
    }
    while(!pq.empty()) {
        etemp=pq.top(); pq.pop();
        v=etemp.second;
        c=etemp.first;
        if(d[v]<c) continue;
        d[v]=c;
        for(auto x : e[v]) {
            if(d[x.second]<=c+x.first) continue;
            pq.push(Edge{c+x.first,x.second});
        }
    }
    for(int i=0; i<n; ++i) {
        cout << i << " " << d[i] << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;
typedef long long ll;
const int INF = 1<<30; 
const int MOD = 1e9 + 7;
const int MAX_N = 110;
int cost[MAX_N][MAX_N], d[MAX_N];
bool used[MAX_N];
void dijkstra(int n)
{
    for(int i = 0; i <= n; i++) { d[i] = INF; used[i] = false; }
    d[0] = 0;
    while(true)
    {
        int v = -1;
        for(int u = 0; u < n; u++)
        {
            if(not used[u] && (v == -1 || d[u] < d[v])) v = u;
        }
        if(v == -1) break;
        used[v] = true;
        for(int u = 0; u < n; u++) d[u] = min(d[u], d[v] + cost[v][u]);
    }
    for(int i = 0; i < n; i++) cout << i << " " << d[i] << endl;
}
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n; cin >> n;
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < n; j++) cost[i][j] = INF;
    }
    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;
            cost[u][v] = c;
        }
    }
    dijkstra(n);
    return 0;
}