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()

	route := make([][]Node, n)
	weight := make([]int, n)
	for i := 0; i < n; i++ {
		weight[i] = NIL
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		route[i] = make([]Node, k)
		for j := 0; j < k; j++ {
			route[u][j] = Node{id: scanInt(), weight: scanInt()}
		}
	}

	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 _, nextNode := range route[node.id] {
			if weight[nextNode.id] != NIL {
				continue
			}
			nextNode.weight += node.weight
			heap.Push(h, nextNode)
		}
	}

	for i, w := range weight {
		fmt.Println(i, w)
	}
}

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]);
	}
}