Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, nodes[i].cost)
	}
	wtr.Flush()
}

C++: #include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <limits>
#include <cmath>
#include <numeric>
#include <string>
#include <queue>

using namespace std;

using ll = long long int;
using ull = unsigned long long int;
#define rep(i, a, b) for(int i = (a); i < (b); ++i )
#define rrep(i, a, b) for(int i = (a); i > (b); --i )
#define REP(i, a, b) for(int i = (a); i <= (b); ++i )
#define RREP(i, a, b) for(int i = (a); i >= (b); --i )
#define llrep(i, a, b) for(ll i = (a); i < (b); ++i )
#define llrrep(i, a, b) for(ll i = (a); i > (b); --i )
#define llREP(i, a, b) for(ll i = (a); i <= (b); ++i )
#define llRREP(i, a, b) for(ll i = (a); i >= (b); --i )
#define ullrep(i, a, b) for(ull i = (a); i < (b); ++i )
#define ullrrep(i, a, b) for(ull i = (a); i > (b); --i )
#define ullREP(i, a, b) for(ull i = (a); i <= (b); ++i )
#define ullRREP(i, a, b) for(ull i = (a); i >= (b); --i )

template<typename T=int>
class UnionFind {
public:
    explicit UnionFind(unsigned long long n) : rank_(n, 0), p_(n, 0) {
        for (T i = 0; i < n; i++) {
            MakeSet(i);
        }
    }

    void MakeSet(T x) {
        p_[x] = x;
        rank_[x] = 0;
    }

    bool Same(T x, T y) {
        return FindSet(x) == FindSet(y);
    }

    void Link(T x, T y) {
        if (rank_[x] > rank_[y]) {
            p_[y] = x;
        } else {
            p_[x] = y;
            if (rank_[x] == rank_[y]) {
                rank_[y]++;
            }
        }
    }

    void Unite(T x, T y) {
        Link(FindSet(x), FindSet(y));
    }

    T FindSet(T x) {
        if (x != p_[x]) {
            p_[x] = FindSet(p_[x]);
        }
        return p_[x];
    }

private:
    std::vector<T> rank_, p_;
};
template<typename NumT = ull, typename CostT = ull>
class Dijkstra {
public:
    Dijkstra(unsigned long long num, CostT max_cost) :
            num_(num),
            max_cost_(max_cost),
            v_(num, std::vector<CostT>(num, max_cost)),
            c_(num, 0),
            d_(num, max_cost),
            p_(num, 0) {
    };


    void ComputeWithQ(NumT start) {
        d_[start] = 0;
        p_[start] = start;
        priority_queue<std::pair<CostT, NumT>> pq;
        pq.push(make_pair(0, start));
        while (!pq.empty()) {
            auto node = pq.top();
            pq.pop();
            auto ni = node.second;
            auto c = -node.first;
            c_[ni] = 1;
            if (d_[ni] < c) {
                continue;
            }
            d_[ni] = c;

            for (int i = 0; i < num_; i++) {
                if(v_[ni][i] == max_cost_) {
                    continue;
                }
                if ((c_[i] != 1) && (d_[i] > (v_[ni][i] + d_[ni]))) {
                    p_[i] = ni;
                    d_[i] = v_[ni][i] + d_[ni];
                    pq.push(make_pair(-d_[i], i));
                }
            }
        }
    }

    void Compute(int start) {
        d_[start] = 0;
        p_[start] = start;
        while (true) {
            int m = -1;
            int min_d = std::numeric_limits<int>::max();
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (min_d > d_[i])) {
                    min_d = d_[i];
                    m = i;
                }
            }
            if (m < 0) {
                break;
            }
            c_[m] = 1;
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (d_[i] > (d_[m] + v_[m][i])) ) {
                    d_[i] = d_[m] + v_[m][i];
                    p_[i] = m;
                }
            }
        }
    }

    void Set(NumT s, NumT d, CostT c) {
        v_[s][d] = c;
    }

    CostT Distance(NumT d) {
        return d_[d];
    }

public:
    NumT num_;
    CostT max_cost_;
    std::vector<std::vector<CostT>> v_;
    std::vector<int> c_;
    std::vector<int> d_;
    std::vector<NumT> p_;
};
int nibutan(int *ary, int ok, int ng) {
    bool is_valid;
    while ( std::abs(ok - ng) > 1) {
        int mid = (ok + ng) / 2;
        // is_valid = check(mid);
        if (is_valid) {
            ok = mid;
        }else{
            ng = mid;
        }
    }
    return ok;
}

template<typename NumT = int, typename CostT = unsigned long long>
class DijkstraQ {
public:
    DijkstraQ(unsigned long long num, CostT max_cost):
    adj_(num, std::vector<std::pair<NumT, CostT>>()),
    c_(num, 0),  d_(num, max_cost)
    {}

    void Compute(NumT start) {
        std::priority_queue<std::pair<CostT, NumT>> q;
        d_[start] = 0;
        q.push(std::make_pair(0, start));

        while(!q.empty()) {
            std::pair<CostT, NumT> node = q.top();
            q.pop();
            auto n = node.second;
            auto c = -node.first;
            c_[n] = 1;
            if (c > d_[n]) {
                continue;
            }
            d_[n] = c;

            for (NumT i = 0; i < adj_[n].size(); i++) {
                auto nn = adj_[n][i].first;
                auto nc = adj_[n][i].second;
                if (c_[nn] > 0) {
                    continue;
                }
                if (d_[nn] > (c + nc)) {
                    d_[nn] = c + nc;
                    q.push(std::make_pair(-d_[nn], nn));
                }
            }
        }
    }

    void Set(NumT s, NumT d, CostT c) {
        adj_[s].push_back(std::make_pair(d, c));
    }

    CostT Distance(NumT d) {
        return d_[d];
    }

    std::vector<CostT> d_;
    std::vector<int> c_;
    std::vector<std::vector<std::pair<NumT, CostT>>> adj_;
};


bool check(int *A, int i) {
    return A[i] < 39;
}
int nibutan(int *A) {
    int ok = 0;
    int ng = 100;
    while (ng - ok > 1) {
        cout << ng << ", " << ok << endl;
        if (check(A, (ng + ok) / 2)) {
            ok = (ng + ok) / 2;
        }else{
            ng = (ng + ok) / 2;
        }
    }
    return ok;
}

ull K;
ull A[200010];
ull L[200010];
ull R[200010];

double f(ull N) {
    ull ret = 0;
    while(N) {
        ret += N%10;
        N /= 10;
    }
    return double(N) / ret;
}


ull N;
constexpr ull MAXCOST = 1000000000000000;

int main() {
    cin >> N;
    Dijkstra<ull, ull> dq(N+1, MAXCOST);
    rep(i, 0, N) {
        ull n, num;
        cin >> n >> num;
        rep(j, 0, num) {
            ull d, c;
            cin >> d >> c;
            dq.Set(n, d, c);
        }
    }
    dq.ComputeWithQ(0);
    rep(i, 0, N) {
        cout << i << " " << dq.Distance(i) << endl;
    }
}