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++: /*
 * Input
 * An edge-weighted graph G (V, E) and the source r.
 *
 * |V| |E| r
 * s0 t0 d0
 * s1 t1 d1
 * :
 * s|E|−1 t|E|−1 d|E|−1
 * |V| is the number of vertices and |E| is the number of edges in G. The graph
 * vertices are named with the numbers 0, 1,..., |V|−1 respectively. r is the
 * source of the graph.
 *
 * si and ti represent source and target vertices of i-th edge (directed) and di
 * represents the cost of the i-th edge.
 *
 * Output
 * c0
 * c1
 * :
 * c|V|−1
 * The output consists of |V| lines. Print the cost of the shortest path from
 * the source r to each vertex 0, 1, ... |V|−1 in order. If there is no path
 * from the source to a vertex, print INF.
 *
 * Constraints
 * 1 ≤ |V| ≤ 100000
 * 0 ≤ di ≤ 10000
 * 0 ≤ |E| ≤ 500000
 * There are no parallel edges
 * There are no self-loops
 */

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

int main() {
  int n, m, source = 0;
  cin >> n; // >> m >> source;
  vector<map<int, int>> adj(100000);

  vector<int> d(100000, 1000000001);
  bool visited[100000];
  int n_visited = 0;

  for (int u, k; cin >> u >> k;) {
    for (int i = 0, v, len; i < k; ++i) {
      cin >> v >> len;
      adj[u][v] = len;
    }
  }

  auto cmp = [&](int s, int t) { return d[s] > d[t]; };
  priority_queue<int, vector<int>, decltype(cmp)> q(cmp);

  d[source] = 0;
  q.push(source);
  while (!q.empty() and n_visited < n) {
    auto u = q.top();
    q.pop();
    if (visited[u])
      continue;
    ++n_visited;
    visited[u] = true;
    for (auto &kv : adj[u]) {
      d[kv.first] = min(d[kv.first], d[u] + kv.second);
      q.push(kv.first);
    }
  }

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

C++: #include<stdio.h>
#include<string.h>
long long arr[205][205];
long long min(long long a,long long b){
	return a>b?b:a;
}
int main() {
    int n,m;
    while(scanf("%d",&n)!=EOF){
    	long long x,y,c,d;
    	for(int i=0;i<205;i++){
    		for(int j=0;j<205;j++){
    		 arr[i][j]=10000000;	
			}
		}
    	for(int j=0;j<n;j++){
    	scanf("%lld %lld",&x,&y);
    	for(int h=0;h<y;h++){
    		scanf("%lld %lld",&c,&d);
    		arr[x][c]=min(arr[x][c],d);
		}
		}
	for(int k=0;k<n;k++){
		for(int i=0;i<n;i++){
			for(int j=0;j<n;j++){
				arr[i][j]=min(arr[i][j],arr[i][k]+arr[k][j]);
			}
		}
	}
	printf("0 0\n");
	for(int i=1;i<n;i++){
    printf("%d %lld\n",i,arr[0][i]);
   }
    }
	return 0;
}

C++: #include <iostream>
#include <queue>
#include <vector>
#include <utility>
using namespace std;
typedef pair<int, int> P;
struct edge {int to, cost;};
const int INF = (1 << 28);
int n;
vector<edge> G[110];


vector<int> dijkstra(int s) {
    priority_queue<P, vector<P>, greater<P>> que;
    que.push(P(0, s));
    vector<int> d(n, INF);
    d[s] = 0;
    while (!que.empty()) {
        P p = que.top(); que.pop();
        int v = p.second;
        if (d[v] < p.first) continue;
        for (auto e: G[v]) {
            if (d[e.to] > d[v] + e.cost) {
                d[e.to] = d[v] + e.cost;
                que.push(P(d[e.to], e.to));
            }
        }
    }
    return d;
}

int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        int u, k, v, c;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            cin >> v >> c;
            G[u].push_back(edge {v, c});
        }
    }
    vector<int> d = dijkstra(0);
    for (int i = 0; i < n; i++) {
        cout << i << " " << d[i] << endl;
    }

    return 0;
}