Go: package main

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

const BIG_COST = 200000

type Path struct {
	node int
	cost int
}

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

	nNodes := scanInt(sc)

	// 各頂点につながる頂点一覧を得るための隣接リスト
	graph := make([][]Path, nNodes)

	for i := 0; i < nNodes; i++ {
		u := scanInt(sc)
		k := scanInt(sc)
		graph[i] = make([]Path, k)
		for d := 0; d < k; d++ {
			graph[u][d] = Path{
				node: scanInt(sc),
				cost: scanInt(sc),
			}
		}
	}

	// 0 から各頂点への最小コストを保存する配列
	minCosts := make([]int, nNodes)

	minCosts[0] = 0
	for i := 1; i < nNodes; i++ {
		minCosts[i] = BIG_COST
	}

	// 各頂点が調査済みかどうかを保持する配列
	checked := make([]bool, nNodes)

	// 最小コストのパスを高速に取得するためのヒープ。
	// コストが小さいものほどルートに来るようにする。
	heap := NewHeap(func(a, b Path) bool {
		return a.cost < b.cost
	})

	heap.insert(Path{node: 0, cost: 0})
	for heap.size > 0 {
		u := heap.extractMax()

		// 隣接行列を使っていた時とは違い、ヒープには
		// 同じノードへのパスが複数含まれうる。そのため既によりコストの低い
		// パスが見つかっている場合は無視する。
		if minCosts[u.node] < u.cost {
			continue
		}

		checked[u.node] = true

		for _, v := range graph[u.node] {
			cost := v.cost + u.cost
			if !checked[v.node] && cost < minCosts[v.node] {
				minCosts[v.node] = cost
				heap.insert(Path{node: v.node, cost: cost})
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i, cost := range minCosts {
		fmt.Fprintf(w, "%d %d\n", i, cost)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

// --- From ALDS1_9_C: Priority Queue

type Heap struct {
	size   int
	heap   []Path
	isHigh func(a, b Path) bool
}

func NewHeap(isHigh func(a, b Path) bool) Heap {
	heap := make([]Path, 1) // 先頭は不使用
	return Heap{size: 0, heap: heap, isHigh: isHigh}
}

func (h *Heap) insert(v Path) {
	h.size += 1
	if h.size > len(h.heap)-1 {
		h.heap = append(h.heap, v)
	} else {
		h.heap[h.size] = v
	}

	for i := h.size; i > 1; {
		parent := i / 2
		if h.isHigh(h.heap[parent], h.heap[i]) {
			break
		}
		h.heap[i], h.heap[parent] = h.heap[parent], h.heap[i]
		i = parent
	}
}

func (h *Heap) extractMax() Path {
	if h.size <= 0 {
		panic("cannot extract from empty heap")
	}

	max := h.heap[1]
	h.heap[1] = h.heap[h.size]
	h.size -= 1
	h.maxHeapify(1)

	return max
}

func (h *Heap) maxHeapify(idx int) {
	left := idx * 2
	right := left + 1
	largest := idx

	if left <= h.size {
		if h.isHigh(h.heap[left], h.heap[idx]) {
			largest = left
		}
		if right <= h.size && h.isHigh(h.heap[right], h.heap[largest]) {
			largest = right
		}
	}

	if largest != idx {
		h.heap[idx], h.heap[largest] = h.heap[largest], h.heap[idx]
		h.maxHeapify(largest)
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
#define reep(i,a,b) for(int i=(a);i<(b);i++)
#define rep(i,n) reep((i),0,(n))
typedef pair<int,int> pii;
#define F first
#define S second

int main(){
    int n;
    cin>>n;
    vector<vector<pii>> vv(n);
    rep(i,n){
        int a;
        cin>>a;
        int m;
        cin>>m;
        rep(j,m){
            int b,c;
            cin>>b>>c;
            vv[a].push_back(pii(b,c));
        }
    }
    priority_queue<pii> pq;
    pq.push(pii(0,0));
    vector<int> dp(n,-1);
    while(pq.size()){
        auto top=pq.top();
        pq.pop();
        if(dp[top.S]>=0) continue;
        dp[top.S]=-top.F;
        for(pii x:vv[top.S]){
            if(dp[x.F]>=0) continue;
            pq.push(pii(top.F-x.S,x.F));
        }
    }
    rep(i,n){
        cout<<i<<" "<<dp[i]<<endl;
    }
}

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

#define NIL -2
#define INF 1000000001

using namespace std;
static const int BLK = 2;
static const int GRY = 1;
static const int WHT = 0;

void dijkstra(const vector<vector<pair<int,int> > > &adj_list, 
                    vector<int> &color, 
                    vector<int> &parent, 
                    vector<int> &minpath,
                    int start_node)
{
    priority_queue<pair<int,int>,vector<pair<int,int> >, greater<pair<int,int> > >  PQ;
    PQ.push(make_pair(start_node,0));

    while(!PQ.empty()){
        pair<int,int> t = PQ.top(); PQ.pop();
        int u = t.second;
        color[u] = BLK;
        if(minpath[u] < t.first) continue;
        for(int i = 0;i < adj_list[u].size();i++){
            int v = adj_list[u][i].first;
            if(color[v] != BLK){
                if(minpath[u] + adj_list[u][i].second < minpath[v]){
                    minpath[v] = minpath[u] + adj_list[u][i].second;
                    parent[v] = u;
                    color[v] = GRY;
                    PQ.push(make_pair(minpath[v],v));
                }  
            }
        }
        
    }

}


int main(){
    int mat_size;
    int node, deg;
    int to,weight;
    int temp;
    int cost = 0;

    scanf("%d",&mat_size);
    vector<vector<pair<int,int> > > adj_list(mat_size);
    vector<int> color(mat_size,WHT);
    vector<int> minpath(mat_size,INF);
    vector<int> parent(mat_size,-1);
    
    for(int i = 0;i < mat_size;i++){
        scanf("%d %d",&node,&deg);
        for(int j = 0;j < deg;j++){
            scanf("%d %d", &to, &weight);
            adj_list[node].push_back(make_pair(to,weight));
        }
    }
    
    minpath[0] = 0;
    dijkstra(adj_list,color,parent,minpath,0);

    for(int i = 0; i < mat_size;i++){
        printf("%d %d\n",i,minpath[i]);
    }

    return 0;   
}

C++: #include<stdio.h>
#include<queue>
#include<string.h>
using namespace std;
#define INF 1 << 30
struct ss{
	int next;
	int to;
	int val;
}e[100050];
int head[100050];
int tot;
void add(int x,int y,int val){
	e[tot].next=head[x];
	e[tot].to=y;
	e[tot].val=val;
	head[x]=tot++;
}
int n;
int vis[100050]={0};
int dis[10005];
void spfa(){
	for(int i=0;i<n;i++){
		dis[i]=INF;
	}
	vis[0]=1;
	dis[0]=0;
	queue<int> st;
	st.push(0);
	while(!st.empty()){
		int t=st.front();
		st.pop();
		vis[t]=0;
		for(int i=head[t];i!=-1;i=e[i].next){
			int to=e[i].to;
			if(dis[to]>dis[t]+e[i].val){
				dis[to]=dis[t]+e[i].val;
				if(!vis[to]){
					st.push(to);
					vis[to]=1;
				}
			}
		}
	}
}
int main(){
	scanf("%d",&n);
	tot=0;
	memset(head,-1,sizeof(head));
	int a,to,val,num;
	for(int i=0;i<n;i++){
		scanf("%d %d",&a,&num);
		for(int j=1;j<=num;j++){
			scanf("%d %d",&to,&val);
			add(a,to,val);
		}
	}
	spfa();
	printf("0 0\n");
	for(int i=1;i<n;i++){
		printf("%d %d\n",i,dis[i]);
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n); i >= 0; i--)
#define REP(i, m, n) for (int i = (int)(m); i <= (int)(n); i++)
#define REPR(i, m, n) for (int i = (int)(m); i >= (int)(n); i--)
#define all(v) v.begin(), v.end()
typedef long long ll;
const int INF = 1001001001;
typedef pair<int,int> pii;

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; }

using Graph = vector<vector<pii> >;

int n;
vector<bool> seen;
vector<int> dist;
priority_queue<pair<int, int> > pq;

void dijkstra(const Graph &G, int v){
  seen[v] = true;

  for(pii p : G[v]){
    int u = p.first;
    int c = p.second;
    if(seen[u] == true) continue;
    if(chmin(dist[u], dist[v]+c)) pq.push(make_pair((-1)*dist[u], u));
  }

  while(!pq.empty()){
    pair<int, int> tmp;
    tmp = pq.top();
    pq.pop();
    if(seen[tmp.second]) continue;
    int nv = tmp.second;
    dijkstra(G, nv);
  }

  return;
}

int main(){
  cin >> n;

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

  seen.assign(n, false);
  dist.assign(n, INF);
  dist[0] = 0;
  dijkstra(G, 0);

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

  return 0;
}