Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

C++: #include <bits/stdc++.h>
using namespace std;

// 総数を1000000007で割った余り
const long long mod = 1e9 + 7;

using ll  = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define ull unsigned long long
#define ld long double
#define vi vector<int>
#define vll vector<ll>
#define vc vector<char>
#define vs vector<string>
#define vpii vector<pii>
#define vpll vector<pll>

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; i++)
#define rep1(i, n) for (int i = 1, i##_len = (n); i <= i##_len; i++)
#define repr(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define rep1r(i, n) for (int i = ((int)(n)); i >= 1; i--)

#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

#define SORT(v, n) sort(v, v + n);
// #define SORT(v, n) stable_sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RSORT(x) sort(rall(x));
#define pb push_back
#define mp make_pair

#define PI (acos(-1))
#define EPS (1e-7)

ull gcd(ull a, ull b) { return b ? gcd(b, a % b) : a; }
ull lcm(ull a, ull b) { return a / gcd(a, b) * b; }

const int MAX   = 100;
const int INF   = (1 << 21);
const int white = 0;
const int gray  = 1;
const int black = 2;

int n, m[MAX][MAX];

int dijkstra() {
    int minV;
    int d[MAX], color[MAX];
    rep(i, n) {
        d[i]     = INF;
        color[i] = white;
    }

    d[0]     = 0;
    color[0] = gray;
    while (1) {
        minV  = INF;
        int u = -1;
        rep(i, n) {
            if (minV > d[i] && color[i] != black) {
                u    = i;
                minV = d[i];
            }
        }
        if (u == -1) break;
        color[u] = black;
        rep(v, n) {
            if (color[v] != black && m[u][v] != INF) {
                if (d[v] > d[u] + m[u][v]) {
                    d[v]     = d[u] + m[u][v];
                    color[v] = gray;
                }
            }
        }
    }
    rep(i, n) { cout << i << " " << (d[i] == INF ? -1 : d[i]) << endl; }
}

// 単一始点最短経路
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    // cout << fixed << setprecision(5);

    cin >> n;
    rep(i, n) {
        rep(j, n) { m[i][j] = INF; }
    }

    int k, c, u, v;
    rep(i, n) {
        cin >> u >> k;
        rep(j, k) {
            cin >> v >> c;
            m[u][v] = c;
        }
    }

    dijkstra();

    return 0;
}

C++: #include <stdio.h>
#define MAX 100
static const int INFTY = (1<<21);
int n,A[MAX][MAX];

void dikusutora();

int main(){
  int i,j,m,k,d,h;
  scanf("%d",&n);
  for(i=0;i<n;i++){
    for(j=0;j<n;j++){
      A[i][j]=INFTY;
    }
  }
  for(i=0;i<n;i++){
    scanf("%d",&m);
    scanf("%d",&k);
    for(j=0;j<k;j++){
      scanf("%d",&d);
      scanf("%d",&h);
      A[m][d]=h;
    }
  }
  dikusutora();
  return 0;
}
void dikusutora(){
  int min,i,e,v;
  int g[MAX],a[MAX];

  for(i=0;i<n;i++){
    g[i]=INFTY;
    a[i]=0;
  }
  g[0]=0;
  a[0]=1;
  
  while(1){
    min=INFTY;
    e=-1;
    for(i=0;i<n;i++){
      if(min>g[i]&&a[i]!=2){
	e=i;
	min=g[i];
      }
    }
    if(e==-1)
      break;
    a[e]=2;
    for(v=0;v<n;v++){
      if(a[v]!=2&&A[e][v]!=INFTY){
	if(g[v]>g[e]+A[e][v]){
	  g[v]=g[e]+A[e][v];
	  a[v]=1;
	}
      }
    }
  }
  for(i=0;i<n;i++){
    printf("%d",i);
    printf(" ");
    if(g[i]==INFTY)
      printf("-1");
    else printf("%d",g[i]);
    printf("\n");
  }
}

C++: #include "bits/stdc++.h"
using namespace std;
int main()
{
    int n, inf = 1000000000;
    scanf("%d", &n);
    vector<vector<int>> a(n, vector<int>(n, inf));
    for (int i = 0, u, k; i < n; i++)
    {
        scanf("%d %d", &u, &k);
        for (int j = 0, v, c; j < k; j++)
        {
            scanf("%d %d", &v, &c);
            a[u][v] = c;
        }
    }
    vector<int> cost(n, inf);
    vector<bool> vis(n, false);
    cost[0] = 0;
    for (int mi = inf, tip = 0; ; mi = inf)
    {
        for (int i = 0; i < n; i++)
        {
            if (!vis[i] && cost[i] < mi)
            {
                mi = cost[i];
                tip = i;
            }
        }
        
        if (mi == inf)
        {
            break;
        }
        vis[tip] = true;
        for (int i = 0; i < n; i++)
        {
            
            if (!vis[i] && a[tip][i] != inf)
            {
                
                if (cost[tip] + a[tip][i] < cost[i])
                {
                    cost[i] = cost[tip] + a[tip][i];
                }
            }
        }
    }
    
    for (int i = 0; i < n; i++)
    {
        printf("%d %d\n", i, cost[i]);
    }
}

C++: #define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;

//#define int long long
#define DBG 1
#define dump(o) if(DBG){cerr<<#o<<" "<<o<<endl;}
#define dumpc(o) if(DBG){cerr<<#o; for(auto &e:(o))cerr<<" "<<e;cerr<<endl;}
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define each(it,c) for(auto it=(c).begin();it!=(c).end();it++)
#define all(c) c.begin(),c.end()
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9 + 7);
const int W = 0; const int B = 1;
int n;
vector<vector<pair<int, int>>>M;
void dijkstra() {
	int minv;
	vector<int>d(n, INF), color(n, W);
	d[0] = 0;
	while (1) {
		minv = INF;
		int u = -1;
		rep(i, 0, n) {
			if (color[i] != B&&d[i] < minv) {
				u = i;
				minv = d[i];
			}
		}
		if (u == -1)break;
		color[u] = B;
		rep(v, 0, M[u].size()) {
			pair<int, int>t(M[u][v]);
			if (color[t.first] != B&&d[u] + t.second < d[t.first]) {
				d[t.first] = d[u] + t.second;
			}
		}
	}
	rep(i, 0, n) {
		cout << i << " " << d[i] << endl;
	}
}
signed main() {
	cin >> n; M = vector<vector<pair<int, int>>>(n, vector<pair<int, int>>());
	rep(i, 0, n) {
		int u, k; cin >> u >> k;
		rep(j, 0, k) {
			int v, c; cin >> v >> c;
			M[u].push_back(make_pair(v, c));
		}
	}
	dijkstra();
	return 0;
}