Go: package main

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

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := make(map[int]int)
	q[0] = 0
	visited := make(map[int]struct{})
	out := make([]int, n)

	for len(q) > 0 {
		u := top(q)
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			if d, ok := q[uu]; !ok || d > q[u]+c {
				q[uu] = q[u] + c
			}
		}

		out[u] = q[u]
		delete(q, u)
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

func top(q map[int]int) int {
	minu := -1
	min := -1
	for u, d := range q {
		if min < 0 || d < min {
			minu = u
			min = d
		}
	}

	return minu
}

C++: #include<bits/stdc++.h>
using namespace std;
const int MAXN = 100+7;
const int INF = 1e6+7;
int m[MAXN][MAXN];
int d[MAXN];
bool visit[MAXN];
int n;
set<int> s;
void djas()
{
    d[0] = 0;
    for(int i = 1; i < n; i++)
    {
        d[i] = INF;
    }
    while(s.size() != n)
    {
        int min_d = INF;
        int s1;
        for(int j = 0; j < n; j++)
        {
            if(d[j]<min_d && visit[j]==false)
            {
                min_d = d[j];
                s1 = j;
            }
        }

        s.insert(s1);
        visit[s1] = true;
        for(int j = 1; j < n; j++)
        {
            if(m[s1][j]!=-1 && d[s1]+m[s1][j]<d[j] && j!=s1 && visit[j]==false){
                d[j] = d[s1]+m[s1][j];
            }
        }
    }
}
int main()
{
//    freopen("in.txt", "r", stdin);
    memset(visit, false, sizeof(visit));
    memset(m, -1, sizeof(m));
    scanf("%d", &n);
    for(int i = 0; i < n; i++)
    {
        int id;
        scanf("%d", &id);
        int degree;
        scanf("%d", &degree);
        for(int j = 0; j < degree; j++)
        {
            int v;
            scanf("%d", &v);
            int c;
            scanf("%d", &c);
            m[id][v] = c;
        }
    }
    djas();
    for(int i = 0; i < n; i++)
    {
        printf("%d %d\n", i, d[i]);
    }

    return 0;
}

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

using namespace std;

#define Vi vector<int>
#define FOR(i,s,e) for (int i=s; i<e; i++)
#define ITER(v) v.begin(), v.end()

constexpr int N_MAX = 100;

int weight[N_MAX][N_MAX];
int dis[N_MAX];

void exhaust_search(const int cur, const int d, const int n, std::array<bool, N_MAX> isvisited) {
    isvisited[cur] = true;
    if (dis[cur] < 0 || d < dis[cur]) { dis[cur] = d; }
    for (int next = 0; next < n; ++next) {
        if (isvisited[next]) { continue; }
        if (weight[cur][next] < 0) { continue; }
        exhaust_search(next, d + weight[cur][next], n, isvisited);
    }
}

void set_shortest_distance(const int n) {
    std::array<bool, N_MAX> isvisited;
    isvisited.fill(false);
    exhaust_search(0, 0, n, isvisited);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    FOR(i,0,n) {
        dis[i] = -1;
        FOR(j,0,n) {
            weight[i][j] = -1;
        }
    }

    int u, k, v, c;
    FOR(i,0,n) {
        cin >> u >> k;
        FOR(j,0,k) {
            cin >> v >> c;
            weight[u][v] = c;
        }
    }

    set_shortest_distance(n);

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

    return 0;
}

C++: #include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
int main() {
	int n, u, k, v, c, i, j, d[100][100], m[100][100], o, p[100] = { 0 }, e, q = 0;
	memset(m, 0x7f, sizeof(m));
	memset(d, 0x7f, sizeof(d));
	d[0][0] = 0;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> u >> k;
		for (j = 0; j < k; j++) {
			cin >> v >> c;
			m[u][v] = c;
		}
	}
	p[0] = 1;
	for (i = 1; i < n; i++) {
		o = d[0][n - 1];
		for (j = 0; j < n; j++) {
			d[i][j] = min(d[i][j], m[q][j] + d[i - 1][q]);
			d[i][j] = min(d[i][j], d[i - 1][j]);
			if (o >= d[i][j] && p[j] == 0) {
				e = j;
				o = d[i][j];
			}
		}
		p[e] = 1;
		q = e;
	}
	for (i = 0; i < n; i++)cout << i << ' ' << d[n - 1][i] << endl;
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#define MAX 101
#define INF 100001
using namespace std;

int n, isSelected[MAX], dist[MAX];
vector<pair<int, int>> ver[MAX];

void initDijkstra(void);
void dijkstra(void);
bool doesFinished(void);

int main() {
	int i, j, id, k, v, c;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> id >> k;
		for (j = 0; j < k; j++) {
			cin >> v >> c;
			ver[id].push_back(make_pair(v, c));
		}
	}

	initDijkstra();

	while (!doesFinished())dijkstra();

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

	return 0;
}

void initDijkstra(void) {
	dist[0] = 0;
	isSelected[0] = 1;
	for (int i = 1; i <= n; i++)dist[i] = INF;
}

void dijkstra(void) {
	int i, minu, minp, mindist = INF;
	vector<pair<int, int>>::iterator itv;
	for (i = 0; i < n; i++) {
		if (isSelected[i] == 0)continue;
		for (itv = ver[i].begin(); itv != ver[i].end(); itv++){
			if (isSelected[itv->first] == 1)continue;
			if (itv->second < mindist) {
				mindist = itv->second;
				minu = itv->first;
				minp = i;
			}
		}
	}
	isSelected[minu] = 1;
	dist[minu] = dist[minp] + mindist;
}

bool doesFinished(void) {
	for (int i = 0; i < n; i++) {
		if (isSelected[i] == 0)return false;
	}
	return true;
}

C++: #define dbg(...) fprintf(stderr,__VA_ARGS__)
#define dpr(x) cerr<<#x<<": "<<x<<endl;
#define dprc(c) do{cerr<<#c<<":";for(auto&_i:(c)){cerr<<" "<<_i;}cerr<<endl;}while(0)
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
int INF = 1e9+7;
#define all(c) (c).begin(), (c).end()
#define tr(i,c) for(auto i=(c).begin();i!=(c).end();i++)
#define rtr(i,c) for(auto i=(c).rbegin();i!=(c).rend();i++)
#define rep(i,b) for(auto i=0;i<(b);i++)
#define pb push_back
#define sz(c) int((c).size())

int main(int argc, char **argv)
{
  int n;
  scanf("%d", &n);

  vector<vector<pii>> G(n, vector<pii>());
  for (int i = 0; i < n; i++) {
    int u, k, v, c;
    scanf("%d %d", &u, &k);
    for (int j = 0; j < k; j++) {
      scanf("%d %d", &v, &c);
      G[u].pb(pii(v, c));
    }
  }

  vi d(n, INF);
  vector<bool> visited(n, false);
  int vc = 0;
  priority_queue<pii, vector<pii>, greater<pii>> q;

  d[0] = 0;
  visited[0] = true;
  vc = 1;
  q.push(pii(0, 0));
  
  while(!q.empty()) {
    pii p = q.top(); q.pop();
    int u = p.second;

    if (d[u] < p.first) continue;

    visited[u] = true;
    for (auto e:G[u]) {
      int v = e.first;
      int c = e.second;
      if (!visited[v] && (d[u] + c < d[v])) {
        d[v] = d[u] + c;
        q.push(pii(d[v], v));
      }
    }
  }

  for (int i = 0; i < n; i++) {
    printf("%d %d\n", i, d[i]);
  }

  return 0;
}