Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

func (h *NodeHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	list := make([][]int, n)
	weight := make([]int, n)
	for i := range list {
		list[i] = make([]int, n)
		weight[i] = NIL
		for j := range list[i] {
			list[i][j] = NIL
		}
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			v := scanInt()
			w := scanInt()
			list[u][v] = w
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for i, w := range list[node.id] {
			if w == NIL {
				continue
			}
			heap.Push(h, Node{id: i, weight: w + node.weight})
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, weight[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: #include <cstdio>
#include <cctype>
#include <climits>
#include <vector>
#include <queue>
using namespace std;

#define si static inline
#define gcu getchar_unlocked
si int in() {
	int c, n = 0;
	bool minus = false;
	if ((c = gcu()) == '-') minus = true; else ungetc(c, stdin);
	while ((c = gcu()) >= '0' && c <= '9') n = 10 * n + (c - '0');
	//return n; }
	return minus ? -n : n; }
si void scan(char *s) {while (!isspace(*s++ = gcu()));}
#define pcu putchar_unlocked
#define svo si void out
template <typename T>
svo(T n) {
	static char buf[20];
	char *p = buf;
	//if(n < 0) pcu('-'), n *= -1;
	if (!n) *p++ = '0';
	else while (n) *p++ = n % 10 + '0', n /= 10;
	while (p != buf) pcu(*--p); }
svo(const char *s){while(*s)pcu(*s++);}
svo(char *s){while(*s)pcu(*s++);}
svo(char c){pcu(c);}
template <typename T>
//svo(vector<T> &v){for(T &x:v)out(' '),out(x);out('\n');}
svo(vector<T> &v){for(T &x:v)out(&x == &v[0]?"":" "),out(x);out('\n');}
template <typename head, typename... tail>
svo(head&& h, tail&&... t){out(h);out(move(t)...);}
#undef svo
#undef si

#define v vector
struct graph {
	struct node {int n, w;};
	v<v<node>> nodes;

	void read(int n) {
		nodes.resize(n);
		for (auto &x: nodes) {
			in();
			for (int k = in(); k--;) {
				int c = in();
				x.push_back({c, in()});
			}
		}
	}

	v<node> dks() {
		v<node> w(nodes.size(), {0, INT_MAX});
		w[0].w = 0;
		priority_queue<node> q;
		q.push({0, 0});
		while (!q.empty()) {
			node n = q.top();
			q.pop();
			if (w[n.n].n)
				continue;
			w[n.n].n = 1;
			for (node &x: nodes[n.n]) {
				w[x.n].w = min(w[x.n].w, n.w + x.w);
				q.push({x.n, w[x.n].w});
			}
		}
		return move(w);
	}
};

bool operator < (const graph::node &a, const graph::node &b) {
	return a.w > b.w;
}

int main() {
	graph g;
	g.read(in());
	int i = 0;
	for (auto &x: g.dks())
		out(i++, ' ', x.w, '\n');
}

C++: #include <iostream>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <set>
#include <string>
#include <cmath>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define REP(i, k, n) for (int i = (int)(k); i < (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rREP(i, k, n) for (int i = (int)(n)-1; i >= k; i--)

#define debug(x) cerr<<#x<<": "<<x<<'\n'

#define fi first
#define se second

#define vi vector<int>
#define pb push_back
#define mp make_pair

#define pcnt __builtin_popcount

typedef long long ll;

const int inf = 100100100;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;

struct Edge{
    int to;
    int cost;
};
vector<vector<Edge> > G(110);
int d[110] = {};
int main(){
    int n;
    cin >> n;
    rep(i,n){
        int t,m;
        cin >> t >> m;
        rep(j,m){
            int a,b;
            cin >> a >> b;
            Edge ee;
            ee.to = a;ee.cost = b;
            G[t].push_back(ee);
        }
    }

    rep(i,n) d[i] = 900010000;
    d[0] = 0;
    while(true){
        bool update = false;
        rep(i,n){
            for(const auto& e: G[i]){
                if(d[i] + e.cost < d[e.to]){
                    d[e.to] = d[i]+e.cost;
                    update = true;
                }
            }
        }
        if(!update) break;
    }

    rep(i,n){
        cout << i << " " << d[i] << endl;
    }

    return 0;
}

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

struct edge { int from, to, cost; };
const int MAX_V=100;
const int INF=1e9;

vector<edge> es;
int d[MAX_V];
int n;

void shortest_path(int s){
  REP(i, n) d[i] = INF;
  d[s] = 0;
  while(true){
    bool update = false;
    for(edge e : es){
      if(d[e.from] != INF && d[e.to] > d[e.from] + e.cost){
	d[e.to] = d[e.from] + e.cost;
	update = true;
      }
    }
    if(!update) break;
  }
}

int main(){
  cin>>n;
  REP(i,n){
    int u, k; cin>>u>>k;
    REP(j,k){
      edge e;
      e.from = u;
      cin>>e.to>>e.cost;
      es.push_back(e);
    }
  }
  shortest_path(0);
  REP(i,n){
    cout<<i<<" "<<d[i]<<endl;
  }
}

C++: #include <iostream>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <set>
#include <cstring>
#include <cmath>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define REP(i, k, n) for (int i = (int)(k); i < (int)(n); i++)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rREP(i, k, n) for (int i = (int)(n)-1; i >= k; i--)

#define debug(x) cerr<<#x<<": "<<x<<'\n'

#define fi first
#define se second

#define vi vector<int>
#define pb push_back
#define mp make_pair

#define pcnt __builtin_popcount

typedef long long ll;

const ll inf = 99900100100;
const int MOD = 998244353;
const double EPS = 1e-9;

vector<vector<pair<int,int> > > G(110);

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int n;
    cin >> n;
    rep(i,n){
      int u,k;
      cin >> u >> k;
      rep(j,k){
        int v,c;
        cin >> v >> c;
        G[u].push_back(mp(v,c));
        G[v].push_back(mp(u,c));
      }
    }
    ll d[110] = {};
    rep(i,110) d[i] = inf;
    d[0] = 0;
    while(true){
        bool update = false;
        rep(i,n){
          for(auto o : G[i]){
            if(d[o.fi] > d[i]+o.se){
                d[o.fi] = d[i]+o.se;
                update = true;
            }
          }
        }
        if(!update) break;
    }
    rep(i,n) cout << i << " " << d[i] << endl;
    return 0;
}

C++: #include <iostream>
#include <set>
using namespace std;
    int d[101];
    int G[101][101]={};
void krusta(int n){
    int color[101],l,m;
    for(int i=0;i<n;i++){
        d[i]=1000000;
        color[i]=0;
    }
    d[0]=0;
    while(1){
        m=1000000;
        for(int i=0;i<n;i++){
            if(color[i]!=1 && d[i]<m){
                m=d[i];
                l=i;
            }
        }
        color[l]=1;
        if(m==1000000){
            break;
        }
        for(int i=0;i<n;i++){
            if(color[i]!=1 && G[l][i]!=0 && G[l][i]+d[l]<d[i]){
                d[i]=G[l][i]+d[l];
            }
        }
    }
}
int main(){
    int n,v,k,c,u;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>u>>k;
        for(int j=0;j<k;j++){
            cin>>v>>c;
            G[u][v]=c;
        }
    }
    krusta(n);
    for(int i=0;i<n;i++){
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}