Go: package main

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

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

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

		out[u] = q[u]
		delete(q, u)
		visited[u] = struct{}{}
	}

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

func top(q map[int]int) int {
	minu := -1
	min := -1
	for u, d := range q {
		if min < 0 || d < min {
			minu = u
			min = d
		}
	}

	return minu
}

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;
}

C++: #include<iostream>
#include<unordered_set>
#define N 105
#define UNDEFINED -1
static const int INF = (1<<21);

int n;
int u, k, v, c;
int G[N][N];
int distance[N], hasVisited[N];


void dijkstra(int s) {
    int minv;
    distance[s] = 0;
    while(true) {
        minv = INF;
        int u = UNDEFINED;
        for (int i = 0; i < n; ++i) {
            if(minv > distance[i] && hasVisited[i] != 1) {
                u = i;
                minv = distance[i];
            }
        }
        if(u == UNDEFINED) break;
        hasVisited[u] = 1;
        for (int v = 0; v < n; ++v) {
            if(distance[v] > distance[u] + G[u][v]) {
                distance[v] = distance[u] + G[u][v];
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        printf("%i %i\n", i, distance[i]);
    }
}

int main() {
    for (int i = 0; i < N; ++i) {
        for (int j = 0; j < N; ++j) {
            G[i][j] = INF;
        }
        distance[i] = INF;
        hasVisited[i] = 0;
    }

    std::cin >> n;
    for (int i = 0; i < n; ++i) {
        std::cin >> u >> k;
        for (int j = 0; j < k; ++j) {
                std::cin >> v >> c;
                G[u][v] = c;
            }
        }

    dijkstra(0);

    return 0;
}