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 <iostream>
#include <vector>
#include <queue>

using ll = long long;
using namespace std;
/* initialize */
int n;
vector<pair<int, int> > adj[10000];

void dijkstra(){
    priority_queue<pair<int,int> > PQ;
    int color[10000];
    int d[10000];
    for (int i = 0; i < n; ++i) {d[i] = INT32_MAX; color[i] = 0;};
    d[0] = 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] == INT32_MAX ? -1 : d[i]) << "\n";
    }
};
/* main */
int main() {
    int k, u, v, c;

    cin >> n;
    for (int i = 0; i < n; ++i) {
        scanf("%d %d", &u, &k);
        for (int j = 0; j < k; ++j) {
            scanf("%d %d", &v, &c);
            adj[u].emplace_back(v,c);
        }
    }
    dijkstra();
    return 0;
}

C++: #include <stdio.h>
#include <vector>
#include <queue>

using namespace std;
#define MAX_N (10010)
#define INF (1000000100)
typedef struct {
    int to;
    int w;
} Edge;

vector<Edge> G[MAX_N];
int n;

int dist[MAX_N];
bool arrived[MAX_N];

void dijkstra(int s)
{
    priority_queue< pair<int, int> > PQ;
    for ( int i = 0; i < n; i++ ) {
	dist[i] = INF;
	arrived[i] = false;
    }

    dist[s] = 0;
    PQ.push(make_pair(0, 0));

    while ( !PQ.empty() ) {
	pair<int, int> u = PQ.top(); PQ.pop();
	if ( u.second > dist[u.first] ) continue;
	arrived[u.first] = true;
	
	for ( int i = 0; i < G[u.first].size(); i++ ) {
	    Edge e = G[u.first][i];
	    if ( !arrived[e.to] && dist[e.to] > (dist[u.first] + e.w) ) {
		dist[e.to] = dist[u.first] + e.w;
		PQ.push(make_pair(e.to, dist[e.to]));
	    }
	}
    }

}

int main()
{
    scanf("%d", &n);
    
    for ( int i = 0; i < n; i++ ) {
	int u, k;
	scanf("%d %d", &u, &k);

	for ( int j = 0; j < k; j++ ) {
	    int v, c;
	    Edge e;
	    scanf("%d %d", &v, &c);
	    e.to = v;
	    e.w = c;
	    G[u].push_back(e);
	}
    }

    dijkstra(0);

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

    return 0;
}

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

#define INF 1000000000
using namespace std;

struct edge {
    int from;
    int to;
    int w;
};
struct node {
    node() : id {-1}, d {INF}, ns {} {};
    node(int i, vector<edge>& vec) : id {i}, d {INF}, ns {vec} {};
    int id;
    int d;
    vector<edge> ns;
};

struct node_s {
    int id;
    int d;
};

vector<int> dijkstra(node* graph, int n, int st){
    auto ds = vector<int>(n, INF);
    auto comp = [](node_s* x, node_s* y){return x->d > y->d;};
    priority_queue<node_s*, vector<node_s*>, decltype(comp)> que(comp);
    node_s* start = new node_s {graph[st].id, 0};
    que.push(start);
    while(que.size()){
        node_s* n = que.top();
    /    cout << n->id << ' ' << n->d << endl;
        que.pop();
        if(n->d < ds[n->id]){
            ds[n->id] = n->d;
            for(auto e : graph[n->id].ns){
                if(ds[e.to] < INF){
                    continue;
                }
                node_s* next_n = new node_s {graph[e.to].id, ds[n->id] + e.w};
                que.push(next_n);
            }
        }
        delete n;
    }
    return ds;
}

int main(){
    cin.sync_with_stdio(false);
    cout.sync_with_stdio(false);
    int n;
    cin >> n;
    node graph[n];
    for(int i = 0; i < n; ++i){
        int id;
        int m;
        cin >> id >> m;
        auto vec = vector<edge>(m);
        int v, c;
        for(int j = 0; j < m; ++j){
            cin >> v >> c;
            vec[j] = edge {id, v, c};
        }
        graph[id] = node(id, vec);
    }
    auto ds = dijkstra(graph, n, 0);
    for(int i = 0; i < n; ++i){
        cout << i << ' ' << ds[i] << endl;
    }
}