Go: package main

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

type Node struct {
	Id int
	Dis int
}

type PriorityQueue []*Node

func (pq PriorityQueue) Len() int { return len(pq) }

func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].Dis < pq[j].Dis
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

func (pq *PriorityQueue) Push(x interface{}) {
	*pq = append(*pq, x.(*Node))
}

func (pq *PriorityQueue) Pop() interface{} {
	n := len(*pq)
	pop := (*pq)[n-1]
	*pq = (*pq)[0:n-1]
	return pop
}

func main() {
	var n int
	fmt.Scan(&n)

	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	g := make([][]int, n)
	c := make([][]int, n)
	pq := make(PriorityQueue, 0, n)
	d := make([]int, n)
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		g[u] = make([]int, k)
		c[u] = make([]int, k)
		for j := 0; j < k; j++ {
			sc.Scan()
			g[u][j], _ = strconv.Atoi(sc.Text())
			sc.Scan()
			c[u][j], _ = strconv.Atoi(sc.Text())
		}

		if u == 0 {
			d[u] = 0
		} else {
			d[u] = 1 << 30
		}
		pq.Push(&Node{u, d[u]})
	}
	heap.Init(&pq)

	for pq.Len() > 0 {
		node := heap.Pop(&pq).(*Node)
		for i := 0; i < len(g[node.Id]); i++ {
			nextId := g[node.Id][i]
			nextDis := node.Dis + c[node.Id][i]
			if nextDis < d[nextId] {
				d[nextId] = nextDis
				heap.Push(&pq, &Node{nextId, nextDis})
			}
		}
	}

	wr := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		wr.WriteString(strconv.Itoa(i))
		wr.WriteString(" ")
		wr.WriteString(strconv.Itoa(d[i]))
		wr.WriteString("\n")
	}
	wr.Flush()
}

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

using namespace std;

int main() {

	int INF = 10000000;

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

	vector<pair<int, int>> G[n];
	for (int i = 0; i < n; ++i) {
		int from;
		scanf("%d", &from);

		int v;
		scanf("%d", &v);

		for (int j = 0; j < v; ++j) {
			int to;
			int w;
			scanf("%d %d", &to, &w);
			G[from].push_back(make_pair(to, w));
		}
	}

	int C[n];
	for (int i = 0; i < n; ++i)
		C[i] = INF;

	int color[n];
	int WHITE = 0;
	int BLACK = 1;
	for (int i = 0; i < n; ++i)
		color[i] = WHITE;

	priority_queue<pair<int, int>> PQ;
	PQ.push(make_pair(0, 0));
	C[0] = 0;
	while (!PQ.empty()) {
		int u = PQ.top().second;
		PQ.pop();
		color[u] = BLACK;
		for (int i = 0; i < (int) G[u].size(); ++i) {
			auto c = G[u][i];
			if (color[c.first] != BLACK && c.second + C[u] < C[c.first]) {
				C[c.first] = c.second + C[u];
				PQ.push(make_pair(C[c.first] * -1, c.first));
			}
		}
	}

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

	return 0;
}

C++: #define ll long long
#define MAX 10000

#inlude <iostream>
#include <vector>
#include <algorithm>
#include <queue>

using namespace std;
static const int INF = (1 << 21);

int n;
priority_queue<pair<int,int>> PQ;
vector<pair<int, int>> adj[MAX];
int color[MAX];
int d[MAX];

void dj(int s){
	for (int i = 0;i < n;i++) {
		d[i]=INF;
		color[i] = 0;
	}
	
	d[s] = 0;
	PQ.push(make_pair(0, 0));
	color[0] = 1;

	while (!PQ.empty()) {
		pair<int, int> f = PQ.top(); 
		PQ.pop();
		int u = f.second;
		color[u] = 2;

		if (d[u] < f.first*(-1)) continue;

		for(int j=0;j<adj[u].size();j++){
			int v = adj[u][j].first;
			if (color[v] == 2) continue;
			if (d[v] > d[u] + adj[u][j].second) {
				d[v] = d[u] + adj[u][j].second;
				PQ.push(make_pair(d[v] * (-1), v));
				color[v] = 1;
			}
		}
	}

	for (int i = 0;i < n;i++) {
		cout << i << " " << (d[i] == INF ? -1 : d[i]) << endl;
	}

}

int main() {
	cin >> n;
	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;
			adj[u].push_back(make_pair(v,c));
		}
	}

	dj(0);

}

C++: // ConanYu's https://vjudge.net/solution/13220749
// semon0x29a's https://vjudge.net/solution/13218148

#include <bits/stdc++.h>
using namespace std;
using LL = long long;
using pi = pair<int, int>;

const int INF = 0x3F3F3F3F;
const int maxN = 10010;

int n;
bool mark[maxN];
LL dis[maxN];
map<pi, LL> path;

void init() {
	memset(dis, 0x3F, sizeof(dis));
}

void dijkstra() {
	dis[0] = 0;
	for (int i=0; i<n; ++i) {
		int marker = 0, amin = INF;
		for (int i=0; i<n; ++i) if (!mark[i]) {
			if (dis[i] < amin) {
				amin = dis[i];
				marker = i;
			}
			mark[marker] = true;
			for (int i=0; i<n; ++i) if (!mark[i]) {
				if (path.count({marker, i}))
				if (dis[i] > dis[marker] + path[{marker, i}])	
					dis[i] = dis[marker] + path[{marker, i}];
			}
		}
	}
}

int main()
{
	init();
	
	scanf("%d", &n);
	for (int i=0; i<n; ++i) 
	{
		int u, k; scanf("%d%d", &u, &k);
		while (k--) {
			int v; LL c; scanf("%d%lld", &v, &c);
			if (path.count({u, v}))
				path[{u, v}] = min(path[{u, v}], c);
			else path[{u, v}] = c;
			path[{v, u}] = path[{u, v}];
		}
	}
	
	dijkstra();
	for (int i=0; i<n; ++i) {
		printf("%d %lld\n", i, dis[i]);
	}
}