Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
)

type Item struct {
	value    int // The value of the item; arbitrary.
	priority int // The priority of the item in the queue.
	// The index is needed by update and is maintained by the heap.Interface methods.
	index int // The index of the item in the heap.
}
type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }
func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].priority < pq[j].priority
}
func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
	pq[i].index = i
	pq[j].index = j
}
func (pq *PriorityQueue) Push(x interface{}) {
	n := len(*pq)
	item := x.(*Item)
	item.index = n
	*pq = append(*pq, item)
}
func (pq *PriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	item.index = -1 // for safety
	*pq = old[0 : n-1]
	return item
}

type Q struct {
	pq *PriorityQueue
	ds map[int]int // It has always same value as pq. For random access.
}

func newQ() *Q {
	pq := new(PriorityQueue)
	heap.Init(pq)
	return &Q{
		pq: pq,
		ds: make(map[int]int),
	}
}
func (q *Q) pop() (u, d int) {
	item := heap.Pop(q.pq).(*Item)
	delete(q.ds, item.value)
	return item.value, item.priority
}
func (q *Q) get(u int) (int, bool) { // returns d
	d, ok := q.ds[u]
	return d, ok
}
func (q *Q) set(u, d int) {
	q.ds[u] = d
	for _, item := range *q.pq {
		if item.value != u {
			continue
		}

		item.priority = d
		heap.Fix(q.pq, item.index)
		return
	}
	heap.Push(q.pq, &Item{
		priority: d,
		value:    u,
	})
}
func (q *Q) len() int {
	return len(q.ds)
}

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := newQ()
	q.set(0, 0)
	visited := make(map[int]struct{})
	out := make([]int, n)

	for q.len() > 0 {
		u, d := q.pop()
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			dd := d + c
			if d, ok := q.get(uu); !ok || d > dd {
				q.set(uu, dd)
			}
		}

		out[u] = d
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

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

#define int long long

int e[111][111],d[111];
int used[111];

signed main(){
  int n;
  cin >> n;
  int INF=1LL<<55LL;
  for(int i=0;i<n;i++)
    for(int j=0;j<n;j++)
      e[i][j] = INF;
  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;
      e[u][v]=min(e[u][v],c);
    }
  }
  memset(used,0,sizeof(used));
  for(int i=0;i<n;i++) d[i]=INF;
  d[0]=0;
  while(1){
    int u=-1;
    for(int i=0;i<n;i++){
      if(used[i]) continue;
      if(d[i]==INF) continue;
      if(u<0||d[i]<d[u]) u=i;
    }
    if(u<0) break;
    used[u]=1;
    for(int i=0;i<n;i++)
      d[i]=min(d[i],d[u]+e[u][i]);
    
  }
  for(int i=0;i<n;i++) cout<<i<<" "<< d[i] << endl;
  return 0;
}

C++: // ref: p302

using System;

public class SingleSourceShortestPath
{
	const int MAX = 100;
	const int INFTY = Int32.MaxValue;
	const int WHITE = 0;
	const int GRAY = 1;
	const int BLACK = 2;

	static int vertexNum; // ????????° = V
	static int[,] M = new int[MAX,MAX]; // ????????????????¨????????????£??\??????

	static void dijkstra() {
		int minv;
		int[] d = new int[MAX]; // ?§????s????????????v?????§??????????????????????¨????
		int[] color = new int[MAX]; // ?¨??????¶???????????§??¨???

		// ?????????
		for (int i = 0; i < vertexNum; i++) {
			d[i] = INFTY;
			color[i] = WHITE; 
		}

		// ????????????????????????
		d[0] = 0;
		color[0] = GRAY;

		while (true) {
			minv = INFTY;
			int u = -1;
			for (int i = 0; i < vertexNum; i++) {
				// ???????¨???????????????????????????´???
				if (minv > d[i] && color[i] != BLACK) {
					u = i;
					minv = d[i]; //????°???????????????´??°
				}
			}
			// ???????????¢?´¢?????????????????????
			if (u == -1)
				break;
			// ?¨????????????????????????´
			color[u] = BLACK;

			for (int v = 0; v < vertexNum; v++) {
				//???????¨?????????????????????????u??¨v?????????????????????
				if (color[v] != BLACK && M[u,v] != INFTY) {
					if (d[v] > d[u] + M[u,v]) {
						d[v] = d[u] + M[u,v];
						color[v] = GRAY;
					}
				}
			}
		}
		// ????????¨?????????????????????
		for (int i = 0; i < vertexNum; i++) {
			Console.WriteLine ("{0} {1}", i, (d[i] == INFTY ? -1 : d[i]));
		}
	}
	public static void Main(String[] args) {
		// ????????°
		vertexNum = int.Parse(Console.ReadLine ());
		// ??????????????????
		for (int i = 0; i < vertexNum; i++) {
			for (int j = 0; j < vertexNum; j++) {
				M[i,j] = INFTY;
			}
		}

		int k, c, u, v;
		for (int i = 0; i < vertexNum; i++) {
			string[] readLine = Console.ReadLine().Split(' ');
			int s = 0;
			u = int.Parse(readLine[s]);	// ????????????
			s++;
			k = int.Parse(readLine[s]); 	// ????¬???°
			for (int j = 0; j < k; j++) {
				s++;
				v = int.Parse(readLine[s]);	// ??£??\?????????????????????
				s++;
				c = int.Parse(readLine[s]); // u??¨v????????????????????????
				M[u, v] = c;
			}
		}
		dijkstra ();
	}
}

C++: #include<iostream>
using namespace std;
static const int MAX = 100;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, M[MAX][MAX];

void dijkstra() {
   int minv;
   int color[MAX], d[MAX];
   
   for(int i = 0; i < n; i++) {
   	  d[i] = INFTY; 
	  color[i] = WHITE;
   } 
   
   d[0] = 0;
   color[0] = GRAY;
   
   while( 1 ) {
      minv = INFTY;
      int u = -1;
      for(int i = 0; i < n; i++) {
      	  if(minv > d[i] && color[i] != BLACK) {
  	      	  minv = d[i];
  	      	  u = i;
  	      }
      }
      if(u == -1) break;
      color[u] = BLACK;
      for(int v =  0; v < n; v++) {
      	  if(color[v] != BLACK && M[u][v] != INFTY) {
  	      	if(d[v] > d[u] + M[u][v]) {
	      	  	d[v] = d[u] + M[u][v];
	      	  	color[v] = GRAY;
      	    }
         }
      }
   }
   
   for(int i = 0; i < n; i++) {
   	   cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl; 
   }
}

int main() {
	cin >> n;
	int u, k, c, v;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][i] = INFTY;
		}
	}
	
	for(int i = 0; i < n; i++) {
		cin >> u >> k;
		for(int j = 0; j < k; j++) {
			cin >> v >> c;
			M[u][v] = c;
		}
	}
	
	dijkstra();
	
	return 0;
}

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

template<typename T> struct Graph {
  struct Edge { int to; T cost; };
  vector<int> prev;
  vector<vector<Edge>> g;
  Graph(int n) : prev(n, -1), g(n) {}

  void addEdge(int u, int v, T w) {
    g[u].push_back({v, w});
    //g[v].push_back({u, w});
  }
  vector<T> dijkstra(int s) {
    vector<T> dist(g.size(), -1);
    using Node = pair<T, int>;
    priority_queue<Node, vector<Node>, greater<Node>> pq;
    pq.push({dist[s] = 0, s});

    while (!pq.empty()) {
      auto d = pq.top().first;
      auto u = pq.top().second;
      pq.pop();
      if (dist[u] < d) continue;
      for (auto&& v : g[u]) {
        if (dist[v.to] < 0 || dist[v.to] > dist[u] + v.cost) {
          dist[v.to] = dist[u] + v.cost;
          prev[v.to] = u;
          pq.push({dist[v.to], v.to});
        }
      }
    }
    return dist;
  }
  vector<int> getPath(int t) {
    vector<int> path;
    for (; t != -1; t = prev[t]) path.push_back(t);
    reverse(begin(path), end(path));
    return path;
  }
};

int main() {
  int n; cin >> n;
  Graph<int> g(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;
      g.addEdge(u, v, c);
    }
  }
  vector<int> d = g.dijkstra(0);
  for (int i = 0; i < n; ++i) {
    cout << i << ' ' << d[i] << endl;
  }
  return 0;
}