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 "bits/stdc++.h"
#define REP(i, n) for(int i = 0; i < n; i++)
#define REPR(i, n) for(int i = n; i >= 0; i--)
#define FOR(i, m, n) for(int i = m; i < n; i++)
#define FORR(i, a, b) for(int i=(b)-1; i>=(a); --i)
#define ALL(v) v.begin(), v.end()
#define FS first
#define SC second
#define SZ(a) int((a).size())
#define SORT(c) sort((c).begin(),(c).end())
#define MEMSET(v, h) memset((v), h, sizeof(v))
#define SQR(x) ((x) * (x))
#define BIT(n) (1LL<<(n))
#define PCNT(x) __builtin_popcountll(x)
#define PB push_back
#define MP make_pair
#define endl "\n"
using namespace std;
typedef long long LL;
typedef long double LD;
typedef vector<int> VI;
typedef vector<LL> VLL;
typedef vector<bool> VB;
typedef vector<vector<int> > VVI;
typedef vector<vector<LL> > VVLL;
typedef vector<vector<bool> > VVB;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef vector<PII> VPII;
const LL MOD=1000000007ll;
const LL INF=2000000000ll;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};

long power(long a,long b){return b?power(a*a%MOD,b/2)*(b%2?a:1)%MOD:1;}

long perm(int N, int K){
	long x=1;
	for(int i=1;i<=K;i++)
	{
		x=x*(N-i+1)%MOD;
	}
	return x%MOD;
}

long factorial(int N){
	return perm(N,N);
}

long comb(int N,int K){
	long x=1,y=1;
	for(int i=1;i<=K;i++)
	{
		x=x*(N-i+1)%MOD;
		y=y*i%MOD;
	}
	return x*power(y,MOD-2)%MOD;
}

long hcomb(int N, int K){
    return comb(N+K-1, N-1);
}

int dtoi(double d){
    if ((double) 2*d-floor(d)-ceil(d) >= 0) return ceil(d);
    else return floor(d);
}

bool isprime(int n) {
    if (n < 2) return false;
    for (int i = 2; i*i <= n; ++i) {
        if (n % i ==  0) return false;
    }
    return true;
}

void eratosthenes(int n){
	// エラトステネスのふるい
    bitset<1000000> is_prime(0); // 十分大きなサイズを確保します
    for (int i = 2; i <= n; ++i) is_prime.set(i); // とりあえず全部ふるいに入れます
    for (int i = 2; i <= n; ++i) {
        if (is_prime[i]) { // 素数 i を発見したら
            for (int j = i * 2; j <= n; j += i) {
                is_prime.reset(j); // i の倍数をふるい落とす
            }
        }
    }
	for (int i = 2; i <= n; ++i) {
        if (is_prime[i]) cout << i << endl;
    }
}

void dfs(const vector<vector<int> > &G, int v, vector<int> &seen) {
    seen[v] = true; // v を訪問済にする

    // v から行ける各頂点 next_v について
    for (int next_v : G[v]) { 
        if (seen[next_v]) continue; // next_v が探索済だったらスルー
        dfs(G, next_v, seen); // 再帰的に探索
    }
}

void bfs(const vector<vector<int> > &G, int v, vector<int> &dist){
    REP(i,SZ(dist)) dist[i] = -1; // 全頂点を「未訪問」に初期化
    queue<int> que;

    // 初期条件 (頂点 0 を初期ノードとする)
    dist[v] = 0;
    que.push(v); // 0 を橙色頂点にする

    // BFS 開始 (キューが空になるまで探索を行う)
    while (!que.empty()) {
        v = que.front(); // キューから先頭頂点を取り出す
        que.pop();

        // v から辿れる頂点をすべて調べる
        for (int next_v : G[v]) {
            if (dist[next_v] != -1) continue; // すでに発見済みの頂点は探索しない

            // 新たな白色頂点 nv について距離情報を更新してキューに追加する
            dist[next_v] = dist[v] + 1;
            que.push(next_v);
        }
    }
}

int knapsack01(int N, int W, vector<int> &value, vector<int> &weight){
    VVI dp(N+1,VI(W+1,0));
    REP(i,N) REP(j,W+1){
        if (j-weight[i] >= 0) dp[i+1][j] = max(dp[i][j-weight[i]] + value[i], dp[i][j]);
        else dp[i+1][j] = dp[i][j];
    }
    return dp[N][W];
}

int knapsack01_reuse(int N, int W, vector<int> &value, vector<int> &weight){
    VI dp(W+1,0);
    dp[0] = 0;
    for (int i = 0; i < N; i++){
        for (int j = W ;j > 0; j--){
            if (j-weight[i] >= 0) dp[j] = max(dp[j],dp[j-weight[i]]+value[i]);
        }
    }
    return dp[W];
}

int knapsack(int N, int W, vector<int> &value, vector<int> &weight){
    VVI dp(N+1,VI(W+1,0));
    REP(i,N) REP(j,W+1){
        dp[i+1][j] = max(dp[i][j],dp[i+1][j]);
        if (j-weight[i] >= 0) dp[i+1][j] = max(dp[i+1][j-weight[i]]+value[i], dp[i+1][j]); 
    }
    return dp[N][W];
}

int knapsack_reuse(int N, int W, vector<int> &value, vector<int> &weight){
    VI dp(W+1,0);
    dp[0] = 0;
    for (int i = 0; i < N; ++i) {
        for (int w = weight[i]; w <= W; ++w) {
            dp[w] = max(dp[w], dp[w - weight[i]] + value[i]);
        }
    }
    return dp[W];
}

int longest_increasing_subsequence(int n, vector<int> &A){
    vector<int> L(n+1,0);
    L[0] = A[0];
    int length = 1;

    FOR(i,1,n){
        if (L[length-1] < A[i]) L[length++] = A[i];
        else *lower_bound(L.begin(),next(L.begin(),length),A[i]) = A[i];
    }

    return length;
}

int longest_common_subsequence(string X, string Y){
    int m = X.length();
    int n = Y.length();
    int res = 0;
    X = ' ' + X;
    Y = ' ' + Y;
    VVI c(m+1, VI(n+1,0));
    FOR(i,1,m+1) FOR(j,1,n+1){
        if (X[i] == Y[j]) c[i][j] = c[i-1][j-1] + 1;
        else c[i][j] = max(c[i-1][j], c[i][j-1]);
        res = max(res,c[i][j]);
    }
    return res;
}

void dijkstra(int n, const vector<vector<pair<int, int> > > &G, int v, vector<int> &dist){
    priority_queue<pair<int, int> > pq;
    vector<int> color(n,0);
    REP(i,n) dist[i] = INF;
    dist[v] = 0;
    pq.push(make_pair(0,v));
    color[v] = 1;

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

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

        REP(j,G[u].size()){
            v = G[u][j].first;
            if (color[v] == 2) continue;
            if (dist[v] > dist[u] + G[u][j].second){
                dist[v] = dist[u] + G[u][j].second;
                pq.push(make_pair(dist[v]*(-1), v));
                color[v] = 1;
            }
        }
    }
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(10);

    int n,u,k,v,c;
    cin >> n;

    vector<vector<pair<int, int> > > G(n);
    VI dist(n,INF);

    REP(i,n) {
        cin >> u >> k;
        REP(j,k){
            cin >> v >> c;
            G[i].push_back(make_pair(v,c));
        }
    }

    dijkstra(n, G, 0, dist);
    REP(i,n) cout << i << " " << dist[i] << endl;
}