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

#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for (int i = x; i < n; i++)
#define OP(m) cout << m << endl
typedef long long ll;
typedef unsigned long long ull;

int main()
{
    int n;
    cin >> n;
    int m[n][n];
    rep(i, n) rep(j, n) m[i][j] = (i == j ? 0 : 1e8);
    rep(i, n)
    {
        int u, k;
        cin >> u >> k;
        rep(i, k)
        {
            int v, c;
            cin >> v >> c;
            m[u][v] = c;
        }
    }

    rep(k, n) rep(i, n) rep(j, n) m[i][j] = min(m[i][j], m[i][k] + m[k][j]);

    rep(i, n) cout << i << " " << m[0][i] << endl;

    return 0;
}

C++: //
// Created by 李青坪 on 2018/11/7.
//

#include <cstdio>
#include <algorithm>
#include <set>

#define MAXN 100
#define INFINITY 1<<21
#define NIL -1
using namespace std;

int n;
int graph[MAXN][MAXN];
int d[MAXN];
int parent[MAXN];
set<int> S;
set<int> V_S;

void init(){
    S.insert(0);
    for (int j = 1; j < n; ++j) {
        V_S.insert(j);
    }
    fill(d, d+n, INFINITY);
    d[0] = 0;
    for (int k = 1; k < n; ++k) {
        d[k] = graph[0][k];
        parent[k] = 0;
    }
    fill(parent, parent+n, NIL);
}

int findMinEdge(){
    int min = INFINITY;
    int u = NIL;
    set<int>::iterator it;
    for (it = V_S.begin(); it != V_S.end(); ++it){
        if (min > d[*it]){
            min = d[*it];
            u = *it;
        }
    }
    return u;
}

void updateMinWeight(int u){
    set<int>::iterator it;
    for (it = V_S.begin(); it != V_S.end(); ++it){
        if (d[u] + graph[u][*it] < d[*it]){
            d[*it] = d[u]  + graph[u][*it];
            parent[*it] = u;
        }
    }
}

void dijkstra(){
    while (!V_S.empty()){
        int u = findMinEdge();
        S.insert(u);
        V_S.erase(V_S.find(u));
        updateMinWeight(u);
    }
}

int main(){
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        fill(graph[i], graph[i]+n, INFINITY);
    }
    int u, k;
    for (int i = 0; i < n; ++i) {
        scanf("%d %d", &u, &k);
        int v, w;
        for (int j = 0; j < k; ++j) {
            scanf("%d %d", &v, &w);
            graph[u][v] = w;
        }
    }
    init();
    dijkstra();
    for (int l = 0; l < n; ++l) {
        printf("%d %d\n", l, d[l]);
    }
}
/*
5
0 3 2 3 3 1 1 2
1 2 0 2 3 4
2 3 0 3 3 1 4 1
3 4 2 1 0 1 1 4 4 3
4 2 2 1 3 3
 */

C++: # include<iostream>
using namespace std;
const int INFTY = (1 << 21);
const int MAX = 100;
const int WHITE = 0;
const int GRAY = 1;
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 (color[i] != BLACK && minv > d[i]) {
				minv = d[i];
				u = 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;
	int u, k, v, d;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = INFTY;
		}
	}
	
	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v >> d;
			M[u][v] = d;
		}
	}

	dijkstra();
	return 0;
}

C++: #include <bits/stdc++.h>

#define rep(i, a, b) for (int i = a; i < (int)(b); ++i)
#define rrep(i, a, b) for (int i = b - 1; i >= (int)(a); --i)

using namespace std;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    vvi g(n, vi(n, INT_MAX));

    rep(i, 0, n) {
        int u, k;
        cin >> u >> k;

        rep(j, 0, k) {
            int v, c;
            cin >> v >> c;
            g[u][v] = c;
        }
    }

    vector<bool> seen(n, false);
    vi ds(n, INT_MAX);

    ds[0] = 0;

    while (true) {
        int minv = INT_MAX;
        int u = -1;

        rep(i, 0, n) {
            if (!seen[i] && ds[i] < minv) {
                minv = ds[i];
                u = i;
            }
        }
        if (u == -1) { break; }
        seen[u] = true;

        rep(v, 0, n) {
            if (!seen[v] && g[u][v] != INT_MAX && ds[v] > minv + g[u][v]) {
                ds[v] = minv + g[u][v];
            }
        }
    }

    rep(i, 0, n) {
        cout << i << " " << ds[i] << endl;
    }

    return 0;
}