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;
#define FOR(i,k,n) for(int i = (k); i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define INF 114514810
#define MOD 1000000007
#define ALL(a) begin(a),end(a)
#define MS(m,v) memset(m,v,sizeof(m))
#define D10  fixed<<setprecision(10)
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> P;
typedef long long ll;
struct edge
{
	int from, to, cost;
	bool operator < (const edge& e) const { return cost < e.cost; }
	bool operator >(const edge& e) const { return cost > e.cost; }
};
///*************************************************************************************///
///*************************************************************************************///
///*************************************************************************************///

int V;
int d[100001];
vector<edge> es[100001];

void dijkstra(int s)
{
	fill(d, d + V, INF);
	d[s] = 0;
	priority_queue<P, vector<P>, greater<P>> que;
	que.push(P(0, s));
	while (!que.empty())
	{
		P p = que.top(); que.pop();
		int v = p.second;
		if (d[v] < p.first) continue;
		REP(i, es[v].size())
		{
			edge e = es[v][i];
			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()
{
	cin >> V;
	REP(i, V)
	{
		int u, k; cin >> u >> k;
		REP(i, k)
		{
			int c, v; cin >> v >> c;
			es[u].push_back(edge{ u, v, c });
		}
	}
	dijkstra(0);
	REP(i, V)
	{
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

C++: #include <stdio.h>
#include <queue>
using namespace std;

#define MAX_N (105)
#define MAX_D (100010)
#define INF (MAX_N * MAX_D)

int n;

int G[MAX_N][MAX_N];
int dist[MAX_N];
bool arrived[MAX_N];

void dijkstra(int s)
{
    for ( int i = 0; i < n; i++ ) dist[i] = INF;

    dist[s] = 0;

    while ( true ) {
	int min_dist = INF;
	int index = -1;
	for ( int i = 0; i < n; i++ ) {
	    if ( !arrived[i] && dist[i] < min_dist ) {
		min_dist = dist[i];
		index = i;
	    }
	}
	
	if ( index == -1 ) break;
	arrived[index] = true;

	for ( int i = 0; i < n; i++ ) {
	    if ( !arrived[i] && G[index][i] != INF ) {
		if ( dist[i] > (dist[index] + G[index][i]) ) {
		    dist[i] = dist[index] + G[index][i];
		}
	    }
	}
    }
}


int main()
{
    scanf("%d", &n);

    for ( int i = 0; i < n; i++ ) {
	for ( int j = 0; j < n; j++ ) {
	    G[i][j] = INF;
	}
    }

    for ( int i = 0; i < n; i++ ) {
	int u, k;
	scanf("%d %d", &u, &k);

	for ( int j = 0; j < k; j++ ) {
	    int v, c;
	    scanf("%d %d", &v, &c);
	    G[u][v] = c;
	}
    }

    dijkstra(0);

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

    return 0;
}

C++: #include <iostream>
#define MAX 100
#define INF (1<<21)
#define WHITE 0
#define GRAY  1
#define BLACK 2 
using namespace std;

int n, adj_M[MAX][MAX];

void Dijkstra()
{
    int next, min_cost;
    int min_dist[n+1], color[n+1], parent[n+1];

    for (int i = 0; i < n; ++i) 
    {
        color[i]  = WHITE;
        parent[i] = -1;
        min_dist[i] = INF;
    }

    min_dist[0] = 0;

    while (true) 
    {
        min_cost = INF;
        next = -1;
        for (int i = 0; i < n; ++i) 
        {
            if (color[i] != BLACK && min_dist[i] < min_cost) 
            {
                min_cost = min_dist[i];
                next = i;
            }
        }
        if (next == -1) break;
        color[next] = BLACK;

        for (int i = 0; i < n; ++i) 
        {
            if (color[i] != BLACK && adj_M[next][i] != INF)
            {
                if (min_dist[next] + adj_M[next][i] < min_dist[i])
                {
                    color[i] = GRAY;
                    min_dist[i] = min_dist[next] + adj_M[next][i];
                    parent[i] = next;
                }
            }
        }
    }

    for (int i = 0; i < n; ++i) 
    {
        cout << i << ' ' << min_dist[i] << endl;
    }
}

int main() 
{
    int id, deg, n_id, n_w;
    cin >> n; 

    for (int i = 0; i < n; ++i) 
    {
        for (int j = 0; j < n; ++j) 
        {
            adj_M[i][j] = INF;
        }
    }

    for (int i = 0; i < n; ++i) 
    {
        cin >> id >> deg;
        for (int j = 0; j < deg; ++j) 
        {
            cin >> n_id >> n_w;
            adj_M[id][n_id] = n_w;
        }
    }

    Dijkstra();
}

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

using namespace std;

int n;
vector<int> g[100];
vector<int> w[100];
int d[100];
char color[100];

void dijkstra() {
    d[0] = 0;
    color[0] = 'b';

    for (int k = 1; k < n; ++k) {
        int next;
        int mine = INT_MAX;
        for (int i = 0; i < n; ++i) {
            if (color[i] == 'b') {
                for (int j = 0; j < g[i].size(); ++j) {
                    if (d[i] + w[i].at(j) <= d[g[i].at(j)] && color[g[i].at(j)] == 'w') {
                        d[g[i].at(j)] = d[i] + w[i].at(j);
                        if (d[g[i].at(j)] <= mine) {
                            next = g[i].at(j);
                            mine = d[next];
                        }
                    }
                }
            }
        }
        color[next] = 'b';
        d[next] = mine;
    }
}

int main() {
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int u;
        int k;
        cin >> u >> k;
        int v, c;
        for (int j = 0; j < k; ++j) {
            cin >> v >> c;
            g[u].push_back(v);
            w[u].push_back(c);
        }
    }
    for (int m = 0; m < n; ++m) {
        color[m] = 'w';
        d[m] = INT_MAX;
    }

    dijkstra();

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

    return 0;
}