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 <cstdio>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

#define rep(i, n) for(int i = 0; i < n; ++i)
const int max_v = 10100;
const int max_e = 505000;
const int inf = 0x3fffffff;

typedef pair<int, int> P;

typedef struct edge {
    int to, dist;
    edge():to(0),dist(0) {}
    edge(int _to, int _dist):to(_to),dist(_dist) {}
    bool operator < (const edge & o) const {
	return dist > o.dist;
    }
}edge;

struct graph {
    int V, E;
    int d[max_v], prev[max_v];
    bool vis[max_v];
    vector<edge> G[max_v];
    graph():V(0),E(0) {}

    graph(int _V):V(_V),E(0) {}

    graph(int _V, int _E, int ed[][3], bool bidirect):V(_V),E(_E) {
	rep(i, E) {
	    int u = ed[i][0], v = ed[i][1], dist = ed[i][2];
	    G[u].push_back(edge(v, dist));
	    if (bidirect) G[v].push_back(edge(v, dist));
	}
    }
    graph(int _V, int g[][max_v]) {
	V = _V; E = 0;
	rep(i, V) rep(j, V)
	    if (g[i][j] != inf) {
		G[i].push_back(edge(j, g[i][j]));
		++E;
	    }
    }

    void add_edge(int u, int v, int c) {
	G[u].push_back(edge(v, c));
    }

    void output() {
	rep(i, V) {
	    printf("[%d] ", i);
	    rep(j, G[i].size()) {
		printf("(%d %d) ", G[i][j].to, G[i][j].dist);
	    }
	    putchar('\n');
	}
    }

    void dijkstra(int g[][max_v], int s) {
	rep(i, V) d[i] = inf;
	rep(i, V) prev[i] = -1;
	rep(i, V) vis[i] = false;

	d[s] = 0;
	rep(i, V) {
	    int tmp = inf;
	    int u = -1;
	    rep(j, V) {
		if(!vis[j] && d[j] < tmp) {
		    tmp = d[j];
		    u = j;
		}
	    }
	    vis[u] = true;
	    rep(j, V) {
		if(!vis[j] && d[u] + g[u][j] < d[j]) {
		    d[j] = d[u] + g[u][j];
		    prev[j] = u;
		}
	    }
	}
    }

    void dijkstra(int s) {
	rep(i, V) d[i] = inf;
	rep(i, V) prev[i] = -1;
	rep(i, V) vis[i] = false;
	
	priority_queue<edge> pq;
	pq.push(edge(s, 0));
	d[s] = 0;

	while(! pq.empty()) {
	    edge e = pq.top(); pq.pop();
	    if(e.dist > d[e.to]) continue;
	    d[e.to] = e.dist;
	    vis[e.to] = true;
	    
	    rep(j, G[e.to].size()) {
		int v = G[e.to][j].to;
		int dist = G[e.to][j].dist;

		if(!vis[v] && d[e.to] + dist < d[v]) {
		    d[v] = d[e.to] + dist;
		    prev[v] = e.to;
		    pq.push(edge(v, d[v]));
		}
	    }
	}
    }
};

int N, M;

void solve() {
    int u, k, v, c;
    scanf("%d", &N);
    graph g = graph(N);
    rep(i, N) {
	scanf("%d%d", &u, &k);
	rep(j, k) {
	    scanf("%d%d", &v, &c);
	    g.add_edge(u, v, c);
	}
    }
    g.dijkstra(0);
    rep(i, N) {
	printf("%d %d\n", i, g.d[i]);
    }
}

int main() {
    solve();
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
constexpr int di[] = {0, 1, 0, -1}, dj[] = {1, 0, -1, 0};
#define rep(i, n) for (int i = 0; i < n; i++)
#define repr(i, n) for (int i = n; i >= 0; i--)
#define sort(v) sort((v).begin(), (v).end())
#define sortr(v) sort((v).rbegin(), (v).rend())
#define all(v) (v).begin(), (v).end()
#define max 10000005
#define nil -1
constexpr int inf = 100000000;

struct edge{
    int to,cost;
};

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

void dic(int s){
    priority_queue<P,vector<P>,greater<P>> que;
    d.resize(max);
   fill(d.begin(),d.end(),inf);
   d[s]=0;
   que.push(P(0,s));
   while(!que.empty()){
       P p=que.top();que.pop();
       int v=p.second;
       if(p.first>d[v]){
           continue;
       }
       for(int i=0;i<g[v].size();i++){ 
           edge e=g[v][i];
           if(d[v]+e.cost<d[e.to]){
               d[e.to]=d[v]+e.cost;
               que.push(P(d[e.to],e.to));
           }
       }
   }
}

int main() {
  int  u,k,v,c;
  cin>>n;
    g.resize(n);
    d.resize(n);
  rep(i,n){
      cin>>u>>k;
      for(int j=0;j<k;j++){
          cin>>v>>c;
          g[u].push_back({v,c});
        }
    }
    dic(0);
    rep(i,n){
        cout<<i<<" "<<d[i]<<endl;
    }
  return 0;
}