Go: package main

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

type Item struct {
	value    int // The value of the item; arbitrary.
	priority int // The priority of the item in the queue.
	// The index is needed by update and is maintained by the heap.Interface methods.
	index int // The index of the item in the heap.
}
type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }
func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].priority < pq[j].priority
}
func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
	pq[i].index = i
	pq[j].index = j
}
func (pq *PriorityQueue) Push(x interface{}) {
	n := len(*pq)
	item := x.(*Item)
	item.index = n
	*pq = append(*pq, item)
}
func (pq *PriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	item.index = -1 // for safety
	*pq = old[0 : n-1]
	return item
}

type Q struct {
	pq *PriorityQueue
	ds map[int]int // It has always same value as pq. For random access.
}

func newQ() *Q {
	pq := new(PriorityQueue)
	heap.Init(pq)
	return &Q{
		pq: pq,
		ds: make(map[int]int),
	}
}
func (q *Q) pop() (u, d int) {
	item := heap.Pop(q.pq).(*Item)
	delete(q.ds, item.value)
	return item.value, item.priority
}
func (q *Q) get(u int) (int, bool) { // returns d
	d, ok := q.ds[u]
	return d, ok
}
func (q *Q) set(u, d int) {
	q.ds[u] = d
	for _, item := range *q.pq {
		if item.value != u {
			continue
		}

		item.priority = d
		heap.Fix(q.pq, item.index)
		return
	}
	heap.Push(q.pq, &Item{
		priority: d,
		value:    u,
	})
}
func (q *Q) len() int {
	return len(q.ds)
}

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := newQ()
	q.set(0, 0)
	visited := make(map[int]struct{})
	out := make([]int, n)

	for q.len() > 0 {
		u, d := q.pop()
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			dd := d + c
			if d, ok := q.get(uu); !ok || d > dd {
				q.set(uu, dd)
			}
		}

		out[u] = d
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

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

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> P;
typedef pair<ll,P>  PP;
typedef vector<ll> Vector;
typedef vector<Vector> DVector;
typedef priority_queue<P, vector<P>, greater<P>> PQueue;

#define fi          first
#define se          second
#define sfi         se.fi
#define sse         se.se
#define pb          push_back
#define INF         INT_MAX
#define MOD         1000000007
#define bcnt        __builtin_popcount
#define all(x)      (x).begin(),(x).end()
#define uni(x)      x.erase(unique(all(x)),x.end())
#define ub(x,y)     (upper_bound(all(x),y)-x.begin())
#define lb(x,y)     (lower_bound(all(x),y)-x.begin())
#define rep(i,n)    repl(i,0,n-1)
#define usort(x)    sort(all(x))
#define dsort(x)    sort(all(x),greater<ll>())
#define mkp(x,y)    make_pair(x,y)
#define mmax(x,y)   (x>y?x:y)
#define mmin(x,y)   (x<y?x:y)
#define maxch(x,y)  x=mmax(x,y)
#define minch(x,y)  x=mmin(x,y)
#define exist(x,y)  (find(all(x),y)!=x.end())
#define each(itr,v) for(auto itr:v)
#define repl(i,a,b) for(ll i=(ll)(a);i<=(ll)(b);i++)
DVector costs;
ll n;
Vector mincost;
void djk(ll start){
  PQueue pq;
  mincost.resize(n,INF);
  pq.push({0,start});
  while(pq.size()){
    P state = pq.top();pq.pop();
    if(mincost[state.se] <= state.fi)continue;
    mincost[state.se] = state.fi;
    rep(i,n)pq.push({mmin(mincost[state.se]+costs[state.se][i],mincost[i]),i});
  }
}

int main(){
  cin.sync_with_stdio(false);
  cin >> n;
  costs.resize(n,Vector(n,INF));
  rep(i,n){
    ll u,k;
    cin >> u >> k;
    rep(j,k){
      ll v,c;
      cin >> v >> c;
      costs[u][v] = c;
    }
  }
  djk(0);
  rep(i,n)cout << i << " " << mincost[i] << endl;
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <climits>
#include <string>
#include <vector>
#include <utility>
#include <functional>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <cassert>

using namespace std;

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

const ll MOD = ll(1e9) + 7;
const ll INF = LLONG_MAX;
const ll MAX_N = ll(1e5) + 5;
const double EPS = 10e-8;
const double PI = 3.14159265359;

#define REP(i, n) for (ll i = 0; i < n; i++)
#define REPR(i, n) for (ll i = n; i >= 0; i--)
#define FOR(i, m, n) for (ll i = m; i < n; i++)

int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};

struct UF {
    static const int MAX_N = 100000;
    int p[MAX_N];
    int r[MAX_N];

    void init(int n) {
        REP(i, n) {
            p[i] = i;
            r[i] = 0;
        }
    }
    int find(int x) {
        if (p[x] == x) return x;
        return p[x] = find(p[x]);
    }
    void unite(int x, int y) {
        x = find(x);
        y = find(y);
        if (x == y) return;
        if (r[x] < r[y]) swap(x, y);
        if (r[x] == r[y]) r[x]++;
        p[y] = x;
    }
    bool same(int x, int y) { return find(x) == find(y); }
};

ll n, d[100000];
vector<P> g[100000];

void dijkstra(ll s) {
    fill(d, d + n, INF);
    d[s] = 0;
    priority_queue<P> que;
    que.push({0, s});
    while (!que.empty()) {
        P p = que.top();
        que.pop();
        ll u = p.second;
        if (p.first > d[u]) continue;
        REP(i, g[u].size()) {
            ll v = g[u][i].first, cost = g[u][i].second;
            if (d[v] > d[u] + cost) {
                d[v] = d[u] + cost;
                que.push({d[v], v});
            }
        }
    }
}

int main() {
    cin >> n;
    REP(i, n) {
        ll from, k;
        cin >> from >> k;
        REP(j, k) {
            ll to, c;
            cin >> to >> c;
            g[from].push_back({to, c});
        }
    }
    dijkstra(0);
    REP(i, n) { cout << i << " " << d[i] << endl; }
    return 0;
}