Go: package main

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

const BIG_COST = 200000

const (
	ST_NOT_YET = iota
	ST_JOINED
)

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	nNodes := scanInt(sc)

	costs := make([][]int, nNodes)
	graph := make([][]int, nNodes)

	states := make([]int, nNodes)
	costSums := make([]int, nNodes)

	for i := 0; i < nNodes; i++ {
		costs[i] = make([]int, nNodes)
		costSums[i] = BIG_COST
	}

	for i := 0; i < nNodes; i++ {
		u := scanInt(sc)
		k := scanInt(sc)
		graph[u] = make([]int, k)
		for d := 0; d < k; d++ {
			v := scanInt(sc)
			graph[u][d] = v
			costs[u][v] = scanInt(sc)
		}
	}

	costSums[0] = 0
	for {
		minCost := BIG_COST
		var u int

		for i, cost := range costSums {
			if states[i] != ST_JOINED && cost < minCost {
				minCost = cost
				u = i
			}
		}

		if minCost == BIG_COST {
			break
		}

		states[u] = ST_JOINED

		for _, v := range graph[u] {
			cost := minCost + costs[u][v]
			if cost < costSums[v] {
				costSums[v] = cost
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i, cost := range costSums {
		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
}

C++: #include <stdio.h>
#include <queue>
using namespace std;
struct side{
    int to;
    int cost;
};
struct walk{
    int now;
    int cost;
};
int main(){
    int n,l,m,d[100];
    queue<walk> q;
    vector<side> map[100];
    walk temp,t;
    side s;
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        scanf("%d%d",&l,&m);
        d[i]=-1;
        for(int j=0;j<m;j++){
            scanf("%d%d",&s.to,&s.cost);
            map[l].push_back(s);
        }
    }
    temp.now=temp.cost=0;
    q.push(temp);
    while(!q.empty()){
        temp=q.front();
        q.pop();
        if(d[temp.now]!=-1&&d[temp.now]<=temp.cost)continue;
        d[temp.now]=temp.cost;
        for(int i=0;i<map[temp.now].size();i++){
            t.cost=temp.cost+map[temp.now][i].cost;
            t.now=map[temp.now][i].to;
            q.push(t);
        }
    }
    for(int i=0;i<n;i++){
        printf("%d %d\n",i,d[i]);
    }
}

C++: #include <bits/stdc++.h>

using namespace std;

struct edge {
  int to, weight;
};

void dijkstra(vector<vector<edge>> graph, int start) {
  int n = graph.size();

  int dist[n];
  for (int i = 0; i < n; i++) {
    dist[i] = INT_MAX;
  }
  dist[start] = 0;

  priority_queue<pair<int, int>> que;
  que.push(make_pair(dist[start], start));
  while (!que.empty()) {
    int v = que.top().second;
    int c = que.top().first;
    que.pop();
    for (int i = 0; i < graph[v].size(); i++) {
      edge e = graph[v][i];
      if (dist[e.to] > c + e.weight) {
        dist[e.to] = c + e.weight;
        que.push(make_pair(dist[e.to], e.to));
      }
    }
  }

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

int main() {
  int n;
  cin >> n;
  vector<vector<edge>> graph;
  graph.resize(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;
      graph[u].emplace_back(edge{v, c});
    }
  }

  dijkstra(graph, 0);
}

C++: #include <cstdio>
#include <vector>
#include <algorithm>
#include <queue>

using namespace std;

using Weight=int;
using DArray=vector<Weight>;
using DMatrix=vector<DArray>;

static const Weight INF=1<<29;

struct Edge {
    size_t src, dst;
    Weight weight;
    Edge() {}
    Edge(size_t src, size_t dst, Weight weight=1):
        src(src), dst(dst), weight(weight)
    {}
};

bool operator<(const Edge &e, const Edge &f) {
    if (e.weight != f.weight) {
        return e.weight > f.weight;
    } else {
        return e.src!=f.src? e.src<f.src : e.dst<f.dst;
    }
}

using Edges=vector<Edge>;
using Vertex=vector<Edge>;
using Graph=vector<Vertex>;

void join(Graph &g, size_t s, size_t d, Weight w=1) {
    // non-directed
    g[s].push_back(Edge(s, d, w));
    g[d].push_back(Edge(d, s, w));
}

void connect(Graph &g, size_t s, size_t d, Weight w=1) {
    // directed
    g[s].push_back(Edge(s, d, w));
}

template <class T>
using lp_queue=priority_queue<T, deque<T>, greater<T>>;

vector<Weight> shortest_distance(const Graph &g, size_t s) {
    /* Dijkstra */
    size_t V=g.size();
    vector<Weight> d(V, INF); d[s]=0;

    lp_queue<pair<Weight, size_t>> q; q.push(make_pair(0, s));
    while (!q.empty()) {
        pair<Weight, size_t> p=q.top(); q.pop();
        size_t v=p.second;
        if (d[v] < p.first) continue;

        for (const Edge &e: g[v])
            if (d[e.dst] > d[v] + e.weight) {
                d[e.dst] = d[v] + e.weight;
                q.push(make_pair(d[e.dst], e.dst));
            }
    }
    return d;
}

int main() {
    size_t n;
    scanf("%zu", &n);

    Graph g(n);
    for (size_t i=0; i<n; ++i) {
        size_t u, k;
        scanf("%zu %zu", &u, &k);

        for (size_t j=0; j<k; ++j) {
            size_t c;
            Weight v;
            scanf("%zu %d", &c, &v);

            connect(g, u, c, v);
        }
    }

    vector<Weight> d=shortest_distance(g, 0);
    for (size_t i=0; i<n; ++i)
        printf("%zu %d\n", i, d[i]);

    return 0;
}

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 d[MAX], color[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)
            {
                u = i;
                minv = d[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;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            M[i][j] = INFTY;
        }
    }

    int k, c, u, v;
    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++: //#define LOCAL

#include<cstdio>
#include<algorithm>
#include<cstring>

using namespace std;

#define rep(a, b) for(int i = a; i <= b; i++)
#define mst(a) memset(a, 0, sizeof(a))

const int MAX = 1e2 + 10;
const int INF = 0x3f3f3f3f;

int g[MAX][MAX];
int dist[MAX];
bool vis[MAX];

void init(int n)
{
	rep(0, n - 1)
	{
		dist[i] = INF;
		for(int j = 0; j < n; j++)
			g[i][j] = INF;
	}
	mst(vis);
	return;
}

void dijkstra(int n)
{
	rep(0, n - 1)
		dist[i] = INF;
	dist[0] = 0;
	rep(0, n - 1)
	{
		int mnidx = -1, mndist = INF;
		for(int j = 0; j < n; j++)
			if(!vis[j] && dist[j] < mndist)
				mnidx = j, mndist = dist[j];
		vis[mnidx] = true;
		for(int j = 0; j < n; j++)
			if(!vis[j])
				dist[j] = min(dist[j], dist[mnidx] + g[mnidx][j]);
	}
	return;
}

int main()
{

#ifdef LOCAL
	freopen("in.txt", "r", stdin);
#endif

	int n;
	while(~scanf("%d", &n))
	{
		init(n);
		rep(0, n - 1)
		{
			int u, v, w, num;
			scanf("%d%d", &u, &num);
			while(num--)
			{
				scanf("%d%d", &v, &w);
				g[u][v] = w;
			}
		}

		dijkstra(n);

		rep(0, n - 1)
			printf("%d %d\n", i, dist[i]);
	}
	return 0;
}