Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type DirectedGraphNodeID int

type DirectedGraphNode struct {
	key         DirectedGraphNodeID
	adjacents   []*DirectedGraphNode
	costs       []int
	distance    int
	predecessor *DirectedGraphNode
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for i := 0; i < nNodes; i++ {
		node := DirectedGraphNode{}
		node.key = DirectedGraphNodeID(i)
		node.distance = infty
		graph.nodes[i] = &node
	}
	return &graph
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(i, j DirectedGraphNodeID, cost int) {
	g.nodes[i].adjacents = append(g.nodes[i].adjacents, g.nodes[j])
	g.nodes[i].costs = append(g.nodes[i].costs, cost)
}

func (g *DirectedGraph) print() {
	for i := 0; i < len(g.nodes); i++ {
		node := g.nodes[i]
		key := node.key
		strings := []string{strconv.Itoa(int(key)), strconv.Itoa(node.distance)}
		for j := 0; j < len(node.adjacents); j++ {
			nodeJ := fmt.Sprintf("(%v, %v)", node.adjacents[j].key, node.costs[j])
			strings = append(strings, nodeJ)
		}
		fmt.Printf("%v\n", strings)
	}
}

func (g *DirectedGraph) relaxEdge(l, r *DirectedGraphNode, w int) {
	if r.distance > l.distance+w {
		// fmt.Printf("%v -> %v, %v\n", l.key, r.key, l.distance+w)
		r.distance = l.distance + w
		r.predecessor = l
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	graph := newDirectedGraph(nNodes)

	for i := 0; i < nNodes; i++ {
		iNode := DirectedGraphNodeID(nextInt())
		nAdjacent := nextInt()
		for j := 0; j < nAdjacent; j++ {
			jNode := DirectedGraphNodeID(nextInt())
			cost := nextInt()
			graph.setAdjacency(iNode, jNode, cost)
		}
	}

	graph.nodes[0].distance = 0
	for iNode := 0; iNode < nNodes; iNode++ {
		for iLeft := 0; iLeft < len(graph.nodes); iLeft++ {
			nodeLeft := graph.nodes[iLeft]
			for iRight := 0; iRight < len(nodeLeft.adjacents); iRight++ {
				nodeRight := nodeLeft.adjacents[iRight]
				cost := nodeLeft.costs[iRight]
				graph.relaxEdge(nodeLeft, nodeRight, cost)
			}
		}
	}

	// graph.print()

	for iNode := 0; iNode < len(graph.nodes); iNode++ {
		node := graph.nodes[iNode]
		fmt.Println(node.key, node.distance)
	}
}

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;
}

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

using namespace std;

int n;
vector<int> g[100];
vector<int> w[100];
int d[100];
char color[100];

void dijkstra() {
    d[0] = 0;
    color[0] = 'b';

    for (int k = 1; k < n; ++k) {
        int next;
        int mine = INT_MAX;
        for (int i = 0; i < n; ++i) {
            if (color[i] == 'b') {
                for (int j = 0; j < g[i].size(); ++j) {
                    if (d[i] + w[i].at(j) <= d[g[i].at(j)] && color[g[i].at(j)] == 'w') {
                        d[g[i].at(j)] = d[i] + w[i].at(j);
                        if (d[g[i].at(j)] <= mine) {
                            next = g[i].at(j);
                            mine = d[next];
                        }
                    }
                }
            }
        }
        color[next] = 'b';
        d[next] = mine;
    }
}

int main() {
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int u;
        int k;
        cin >> u >> k;
        int v, c;
        for (int j = 0; j < k; ++j) {
            cin >> v >> c;
            g[u].push_back(v);
            w[u].push_back(c);
        }
    }
    for (int m = 0; m < n; ++m) {
        color[m] = 'w';
        d[m] = INT_MAX;
    }

    dijkstra();

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

    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;

const int INF = 0xfffffff;
const int MAX = 10000;

struct Edge {
	bool operator < (const Edge& e)const {
		return c > e.c;
	}
	int v;
	int c;
};

int main() {
	int n;
	vector<Edge> graph[MAX];
	priority_queue<Edge> q;
	int table[MAX];
	bool check[MAX];

	cin >> n;
	for (int i = 0; i < n; i++) {
		table[i] = INF;
		check[i] = false;
	}

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			Edge e;
			cin >> e.v >> e.c;
			graph[u].push_back(e);
		}
	}

	int u = 0;
	table[0] = 0;
	while (true) {
		check[u] = true;

		for (int i = 0; i < graph[u].size(); i++) {
			int v = graph[u][i].v;
			int c = graph[u][i].c;
			if (table[v] > c + table[u]) {
				table[v] = c + table[u];
				Edge e;
				e.v = v;
				e.c = table[v];
				q.push(e);
			}
		}
		if (check[q.top().v])break;
		u = q.top().v; q.pop();
	}

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

	return 0;
}