Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type DirectedGraphNodeID int

type DirectedGraphNode struct {
	key         DirectedGraphNodeID
	adjacents   []*DirectedGraphNode
	costs       []int
	distance    int
	predecessor *DirectedGraphNode
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for i := 0; i < nNodes; i++ {
		node := DirectedGraphNode{}
		node.key = DirectedGraphNodeID(i)
		node.distance = infty
		graph.nodes[i] = &node
	}
	return &graph
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(i, j DirectedGraphNodeID, cost int) {
	g.nodes[i].adjacents = append(g.nodes[i].adjacents, g.nodes[j])
	g.nodes[i].costs = append(g.nodes[i].costs, cost)
}

func (g *DirectedGraph) print() {
	for i := 0; i < len(g.nodes); i++ {
		node := g.nodes[i]
		key := node.key
		strings := []string{strconv.Itoa(int(key)), strconv.Itoa(node.distance)}
		for j := 0; j < len(node.adjacents); j++ {
			nodeJ := fmt.Sprintf("(%v, %v)", node.adjacents[j].key, node.costs[j])
			strings = append(strings, nodeJ)
		}
		fmt.Printf("%v\n", strings)
	}
}

func (g *DirectedGraph) relaxEdge(l, r *DirectedGraphNode, w int) {
	if r.distance > l.distance+w {
		// fmt.Printf("%v -> %v, %v\n", l.key, r.key, l.distance+w)
		r.distance = l.distance + w
		r.predecessor = l
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	graph := newDirectedGraph(nNodes)

	for i := 0; i < nNodes; i++ {
		iNode := DirectedGraphNodeID(nextInt())
		nAdjacent := nextInt()
		for j := 0; j < nAdjacent; j++ {
			jNode := DirectedGraphNodeID(nextInt())
			cost := nextInt()
			graph.setAdjacency(iNode, jNode, cost)
		}
	}

	graph.nodes[0].distance = 0
	for iNode := 0; iNode < nNodes; iNode++ {
		for iLeft := 0; iLeft < len(graph.nodes); iLeft++ {
			nodeLeft := graph.nodes[iLeft]
			for iRight := 0; iRight < len(nodeLeft.adjacents); iRight++ {
				nodeRight := nodeLeft.adjacents[iRight]
				cost := nodeLeft.costs[iRight]
				graph.relaxEdge(nodeLeft, nodeRight, cost)
			}
		}
	}

	// graph.print()

	for iNode := 0; iNode < len(graph.nodes); iNode++ {
		node := graph.nodes[iNode]
		fmt.Println(node.key, node.distance)
	}
}

C++: #include <iostream>
#include <vector>
#include <map>
#include <unordered_map>
#include <queue>
#include <set>
#include <algorithm>
#include <string>
#include <math.h>
#include <limits.h>
#include <stack>
#include <complex>
#include <stdlib.h>
#include <stdio.h>
#include <functional>
#include <cfloat>
#include <math.h>
#include <numeric>
#include <string.h>
#include <sys/time.h>
#include <random>


#define fs first
#define sc second

using namespace std;

typedef long long ll;
typedef unsigned int uint;
typedef pair<ll, ll> P;

ll squareDis(P x, P y){
    return (x.fs - y.fs) * (x.fs - y.fs) + (x.sc - y.sc) * (x.sc - y.sc);
}

bool judgeAcute(P x, P y, P z){
    ll dis1 = squareDis(x, y);
    ll dis2 = squareDis(x, z);
    ll dis3 = squareDis(y, z);

    return dis1 + dis2 > dis3;

}

class Graph{
    struct edge{
        int vertice;
        ll weight;
    };

    vector<vector<edge>> g;
    unsigned int n;

public:
    Graph(unsigned int n): n{n}{
        g.resize(n);
    }

    void add_edge(int u, int v){
        g[u].emplace_back(edge{v, 1});
    };

    void add_edge(int u, int v, ll w){
        g[u].emplace_back(edge{v, w});
    }

    vector<edge>& get_edge(int v){
        return g[v];
    }

    unsigned int get_num_vertices(){
        return n;
    }

    vector<edge>& operator[](int v){
        return get_edge(v);
    }
};


/**
 *
 * @param s 始点
 * @param g グラフ
 * @return sから各頂点への距離
 */
vector<ll> dijkstra1(int s, Graph g, ll INF=LONG_LONG_MAX / 3){
    unsigned int n = g.get_num_vertices();
    vector<bool> used(n, false);
    vector<ll> d(n, INF);

    d[s] = 0;
    while(true){
        int v = -1;
        for(int u = 0; u < n; u++) {
            if (!used[u] && (v == -1 || d[u] < d[v])) {
                v = u;
            }
        }

        if(v == -1) break;

        used[v] = true;
        for(auto e: g[v]){
            d[e.vertice] = min(d[e.vertice], d[v] + e.weight);
        }
    }

    return d;
}


vector<ll> dijkstra2(int s, Graph g, ll INF=LONG_LONG_MAX / 3){
    typedef pair<ll, int> Ptmp;  // firstは最短距離、secondは頂点の番号

    unsigned int n = g.get_num_vertices();
    priority_queue<Ptmp, vector<Ptmp>, greater<Ptmp>> que;
    vector<ll> d(n, INF);

    d[s] = 0;
    que.push(Ptmp(d[s], s));

    while(!que.empty()){
        Ptmp p = que.top();   que.pop();
        int v = p.second;
        if(d[v] < p.first) continue;
        for(auto e: g[v]){
            if(d[e.vertice] > d[v] + e.weight){
                d[e.vertice] = d[v] + e.weight;
                que.push(Ptmp(d[e.vertice], e.vertice));
            }
        }
    }

    return d;
}



int main(){
    uint n;  cin >> n;
    Graph g(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;
            g.add_edge(u, v, c);
        }
    }

    vector<ll> res = dijkstra2(0, g);
    for(int i = 0; i < n; i++){
        cout << i << " " << res[i] << endl;
    }
}


//int main(){
//    int n, m;   cin >> n >> m;
//
//    vector<vector<edge>> g(100);
//    vector<P> cor(n);
//
//    for(int i = 0; i < n; i++){
//        int x, y;   cin >> x >> y;
//        cor[i] = P(x, y);
//    }
//    for(int i = 0; i < m; i++){
//        int a, b, c;    cin >> a >> b >> c;
//        a--; b--;
//        g[a].emplace_back(edge{c, b});
//        g[b].emplace_back(edge{c, a});
//    }
//
//    vector<vector<edge>> g2;
//    map<P, int> mp;
//    g2.emplace_back(vector<edge>(0));
//    int n2 = 0;
//    mp[P(0, 0)] = n2++;
//
//    for(int i = 0; i < n; i++){
//        for(auto v: g[i]){
//            g2.emplace_back(vector<edge>(0));
//            mp[P(i, v.v)] = n2++;
//        }
//    }
//
//    for(int i = 0; i < n; i++){
//        for(auto v: g[i]){
//            for(auto u: g[i]){
//                if(!judgeAcute(cor[i], cor[u.v], cor[v.v])){
//                    g2[mp[P(i, v.v)]].emplace_back(edge{u.w, mp[P(u.v, i)]});
//                }
//            }
//        }
//    }
//
//
//
//    return 0;
//}