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 <algorithm>
#include <vector>
#include <queue>
const int MAX_N = 10000;
const int INF = 999999999;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
using namespace std;

int n;
vector<pair<int, int> > adj[MAX_N];
int color[MAX_N];
int d[MAX_N];

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

    d[s] = 0;
    PQ.push(make_pair(0, 0));
    color[s] = GRAY;

    while (!PQ.empty()) {
        pair<int, int> edge = PQ.top(); PQ.pop();
        int u = edge.second;
        color[u] = BLACK;

        if (d[u] < edge.first * (-1)) continue;

        for (int i = 0; i < adj[u].size(); i++) {
            int v = adj[u][i].first;
            if (color[v] == BLACK) continue;
            if (d[v] > d[u] + adj[u][i].second) {
                d[v] = d[u] + adj[u][i].second;
                PQ.push(make_pair(d[v]*-1, v));
                color[v] = GRAY;
            }
        }

    }
}

int main(void) {
    cin >> 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;
            adj[i].push_back(make_pair(v, c));
        }
    }

    dijkstra(0);

    for (int i = 0; i < n; i++) {
        cout << i << " " << d[i] << endl;
    }

    return 0;
}

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

typedef long long int ll;

#define BIG_NUM 2000000000

using namespace std;

struct Node {
    Node(int arg_to, int arg_cost) {
        to = arg_to;
        cost = arg_cost;
    }
    
    bool operator<(const struct Node &arg) const{
        return cost > arg.cost;
    };
    
    int to, cost;
};

int main() {
    int N;
    scanf("%d", &N);
    
    vector<Node> V[N];
    
    int node, num, to, cost, D[N];
    
    for(int loop = 0; loop < N; loop++) {
        scanf("%d", &node);
        scanf("%d", &num);
        
        for(int i = 0; i < num; i++) {
            scanf("%d %d", &to, &cost);
            V[node].push_back(Node(to, cost));
        }
        D[loop] = BIG_NUM;
    }
    
    D[0] = 0;
    
    priority_queue<Node> Q;
    
    for(int i = 0; i < V[0].size(); i++) {
        D[V[0][i].to] = V[0][i].cost;
        Q.push(Node(V[0][i].to, V[0][i].cost));
    }
    
    int min_index;
    
    while(!Q.empty()) {
        if(Q.top().cost == D[Q.top().to]) {
            min_index = Q.top().to;
            Q.pop();
        }else {
            Q.pop();
            continue;
        }
        
        for(int k = 0; k < V[min_index].size(); k++) {
            if(D[V[min_index][k].to] > D[min_index] + V[min_index][k].cost) {
                D[V[min_index][k].to] = D[min_index] + V[min_index][k].cost;
                Q.push(Node(V[min_index][k].to, D[V[min_index][k].to]));
            }
        }
    }
    
    for(int i = 0; i < N; i++) printf("%d %d\n", i, D[i]);
    
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> node;
typedef vector<node> Adj_list;
typedef vector<Adj_list> Adj_lists;

class less_cost{
public:
  bool operator()(const pair<int, int> lhs, const pair<int, int> rhs) const{
    return lhs.second < rhs.second;
  }
};

int main(){

  int n;
  scanf("%d", &n);

  Adj_lists adj_lists(n);

  // read weigts
  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;
      scanf("%d %d", &v, &c);
      adj_lists.at(u).push_back(node(v, c));
    }
  }

  // initialize cost
  vector<int> d(n, INT_MAX);
  d.at(0) = 0;
  priority_queue<node, vector<node>, less_cost> pq;
  pq.push(node(0, d.at(0)));
  vector<bool> is_belong_to_sssp(n, false);

  //dijkstra's algorithm
  while(!pq.empty()){
    // extract node u in V-S that has minimum cost
    const node u = pq.top();
    pq.pop();
    is_belong_to_sssp.at(u.first) = true;

    // if u's cost is larger than d[u],
    // than ignore this one
    if(u.second < d.at(u.first)) continue;

    // update node in V-S and adjacent to u
    for(const node& v : adj_lists.at(u.first)){
      if(!is_belong_to_sssp.at(v.first) && d.at(u.first) + v.second < d.at(v.first)){
        d.at(v.first) = d.at(u.first) + v.second;
        pq.push(node(v.first, d.at(v.first)));
      }
    }
  }

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

  return 0;
}