Go: package main

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

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

func (h *NodeHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	route := make([][]Node, n)
	weight := make([]int, n)
	for i := 0; i < n; i++ {
		weight[i] = NIL
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		route[i] = make([]Node, k)
		for j := 0; j < k; j++ {
			route[u][j] = Node{id: scanInt(), weight: scanInt()}
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for _, nextNode := range route[node.id] {
			if weight[nextNode.id] != NIL {
				continue
			}
			nextNode.weight += node.weight
			heap.Push(h, nextNode)
		}
	}

	for i, w := range weight {
		fmt.Println(i, w)
	}
}

C++: #include <cstdio>
#include <cctype>
#include <climits>
#include <vector>
#include <queue>
using namespace std;

#define si static inline
#define gcu getchar_unlocked
si int in() {
	int c, n = 0;
	bool minus = false;
	if ((c = gcu()) == '-') minus = true; else ungetc(c, stdin);
	while ((c = gcu()) >= '0' && c <= '9') n = 10 * n + (c - '0');
	//return n; }
	return minus ? -n : n; }
si void scan(char *s) {while (!isspace(*s++ = gcu()));}
#define pcu putchar_unlocked
#define svo si void out
template <typename T>
svo(T n) {
	static char buf[20];
	char *p = buf;
	//if(n < 0) pcu('-'), n *= -1;
	if (!n) *p++ = '0';
	else while (n) *p++ = n % 10 + '0', n /= 10;
	while (p != buf) pcu(*--p); }
svo(const char *s){while(*s)pcu(*s++);}
svo(char *s){while(*s)pcu(*s++);}
svo(char c){pcu(c);}
template <typename T>
//svo(vector<T> &v){for(T &x:v)out(' '),out(x);out('\n');}
svo(vector<T> &v){for(T &x:v)out(&x == &v[0]?"":" "),out(x);out('\n');}
template <typename head, typename... tail>
svo(head&& h, tail&&... t){out(h);out(move(t)...);}
#undef svo
#undef si

#define v vector
struct graph {
	struct node {int n, w;};
	v<v<node>> nodes;

	void read(int n) {
		nodes.resize(n);
		for (auto &x: nodes) {
			in();
			for (int k = in(); k--;) {
				int c = in();
				x.push_back({c, in()});
			}
		}
	}

	v<node> dks() {
		v<node> w(nodes.size(), {0, INT_MAX});
		w[0].w = 0;
		priority_queue<node> q;
		q.push({0, 0});
		while (!q.empty()) {
			node n = q.top();
			q.pop();
			if (w[n.n].n)
				continue;
			w[n.n].n = 1;
			for (node &x: nodes[n.n]) {
				w[x.n].w = min(w[x.n].w, n.w + x.w);
				q.push({x.n, w[x.n].w});
			}
		}
		return move(w);
	}
};

bool operator < (const graph::node &a, const graph::node &b) {
	return a.w > b.w;
}

int main() {
	graph g;
	g.read(in());
	int i = 0;
	for (auto &x: g.dks())
		out(i++, ' ', x.w, '\n');
}

C++: #include <iostream>
#include <set>
#include <vector>
#include <queue>
#include <stack>
#include <utility>
#include <algorithm>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

class path{
public:
    int from;
    int to;
    int dist;
    path(){
        from = -1;
        to = -1;
        dist = -1;
    }
    path(int from_,int to_,int dist_){
        from = from_;
        to = to_;
        dist = dist_;
    }
    static bool compare(const path& a,const path& b) {
        return a.from < b.from;
    }
    bool operator<(const path& e) const {
        return this->dist < e.dist;
    }
};

int n,u,k,v,c;
vector<path> w;
ll d[10000];

int main() {
    for(int i = 0;i < 10000;i++)d[i] = -NIL;
    cin >> n;
    for(int i = 0;i < n;i++) {
        cin >> u >> k;
        for(int j = 0;j < k;j++) {
            cin >> v >> c;
            w.push_back(path(u,v,c));
        }
    }
    sort(w.begin(),w.end(),path::compare);
    priority_queue<pair<int,int>> q;
    q.push(make_pair(0,0));
    d[0] = 0;
    while(!q.empty()) {
        auto y = q.top();q.pop();
        if(d[y.second] != y.first) continue;
        auto r = lower_bound(w.begin(),w.end(),path(y.second,0,0),path::compare);
        auto l = lower_bound(w.begin(),w.end(),path(y.second+1,0,0),path::compare);
        for(auto itr = r;itr < l;itr++) {
            if(d[itr->to] > d[itr->from] + itr->dist) {
                d[itr->to] = d[itr->from] + itr->dist;
                q.push(make_pair(d[itr->to],itr->to));
            }
        }
    }
    for(int i = 0;i < n;i++){
        cout << i << " " << d[i] << endl;
    }
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <climits>
#include <queue>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define repR(i, n) for(int i = (n) - 1; i > -1; i--)
#define rep1(i, n) for(int i = 1; i < (int)(n + 1); i++)
#define rep1R(i, n) for(int i = (n); i > 0; i--)
using namespace std;
static const int MAX = 10010;
static const int INF = INT_MAX;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

struct Node {
  int v, c;
};

bool operator > (const Node& v1, const Node& v2) {
  return v1.c > v2.c;
}

static const int N = 2010;
vector<Node> adj[MAX];
int color[N];
int d[N];
int n;

void dijkstra(int s) {
  rep(u, n) {
    color[u] = WHITE;
    d[u] = INF;
  }
  d[s] = 0;

  priority_queue<Node, vector<Node>, greater<Node>> PQ;
  PQ.push(Node{s, 0});

  while (!PQ.empty()) {
    Node n = PQ.top(); PQ.pop();
    int u = n.v;
    int c = n.c;

    color[u] = BLACK;

    if (d[u] < c) continue;

    rep(i, adj[u].size()) {
      Node nextNode = adj[u][i];
      int v = nextNode.v;
      if (color[v] != BLACK) {
        if (d[u] + nextNode.c < d[v]) {
          d[v] = d[u] + nextNode.c;
          color[v] = GRAY;
          PQ.push(Node {v, d[v]});
        }
      }
    }
  }
}

int main() {
  cin >> n;
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    rep(j, k) {
      int v, c;
      cin >> v >> c;
      adj[u].push_back(Node {v, c});
    }
  }
  dijkstra(0);
  rep(v, n) cout << v << " " << d[v] << endl;
  return 0;
}

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

static const int MAX = 10000;
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 (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(int argc, char const* argv[])
{
    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;
}