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++: //Single Source Shortest Path I
#include <iostream>
#include <climits>
using namespace std;

static const int N = 100;
static const int WHITE = 0;
static const int BLACK = 1;
int n, A[N][N], colors[N], d[N];

void dijkstra() {
    int u, mind;
    for(int i = 0; i < N; i++) {
        colors[i] = WHITE;
        d[i] = INT_MAX;
    }
    d[0] = 0;
    while(1) {
        u = -1;
        mind = INT_MAX;
        for(int i = 0; i < n; i++) {
            if(colors[i] == WHITE && d[i] < mind) {
                u = i;
                mind = d[i];
            }
        }
        if(u == -1) break;
        colors[u] = BLACK;
        for(int i = 0; i < n; i++) {
            if(A[u][i] != -1) {
                d[i] = min(d[i], mind + A[u][i]);
            }
        }
    }

}

int main() {
    int u, k, v, c;
    cin >> n;
    for(int i = 0; i < N; i++) {
        for(int j = 0; j < N; j++) {
            A[i][j] = -1;
        }
    }
    for(int i = 0; i < n; i++) {
        cin >> u >> k;
        for(int j = 0; j < k; j++) {
            cin >> v >> c;
            A[u][v] = c;
        }
    }

    dijkstra();

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

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef vector<vector<int> > vvi;
typedef vector<int> vi;
typedef vector<vector<bool> > vvb;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef pair<string, int> psi;
typedef pair<int, int> pii;
#define rep(i,s,n) for(int i = (s); i < (n); i++)
#define all(x) (x).begin(), (x).end()
#define yn(f) (f?"yes":"no")
#define YN(f) (f?"YES":"NO")
#define Yn(f) (f?"Yes":"No")
#define mod 1000000007
#define intmax 2147483647
#define intmin -2147483648
#define longmax 9223372036854775807
#define longmin -9223372036854775808
int main() {
	int N;
	cin >> N;
	vvi A(N,vi(N,intmax));
	vi color(N,0);
	vi mincost(N,intmax);
	for (int i = 0; i < N; i++)
	{
		int u,k;
		cin >> u>>k;
		A[i].push_back(u);
		for (int j = 0; j < k; j++)
		{
			int v, w;
			cin >> v >> w;
			A[u][v] = w;
		}
	}
	color[0] = 127;
	mincost[0] = 0;
	while (true) {
		int minIndex = -1;
		for (int i = 0; i < N; i++)
		{
			if (color[i]==127&&(minIndex==-1||mincost[i]<mincost[minIndex]))minIndex = i;
		}
		if (minIndex==-1) break;
		color[minIndex] = 255;
		for (int i = 0; i < N; i++)
		{
			if (color[i]!=255&&A[minIndex][i]<intmax) {
				mincost[i] = min(mincost[i],mincost[minIndex]+ A[minIndex][i]);
				color[i] = 127;
			}
		}
	}
	for (int i = 0; i < N; i++)
	{
		cout << i << " " << mincost[i] << endl;
	}
};

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#define INF 1<<30
using namespace std;
int n;
int A[1000][1000];
int d[1000];
bool used[1000];
int D[1000][1000];

void Init(int f){
  for(int i=0;i<f;i++){
    for(int j=0;j<f;j++)D[i][j] = INF;
  }

}

void djkstra(){
  for(int i=0;i<n;i++){
    d[i] = INF;
    used[i] = false;
  }
  d[0] = 0;

  while(true){
    int v = -1;
    for(int i=0;i<n;i++){
      if(!used[i] && (v == -1 || d[v] > d[i]))v = i;
    }
    if(v == -1)break;
    used[v] = true;
    for(int i=0;i<n;i++){
      d[i] = min(d[i],d[v] + D[v][i]);
    }
  }
}



int main(){
  scanf("%d",&n);
  int u,k,C,V;
  Init(n);
 
  for(int i=0;i<n;i++){
      scanf("%d %d",&u,&k);     
      for(int j=0;j<k;j++){
	scanf("%d %d",&V,&C);
	D[u][V] = C;
	D[V][u] = C;
      }     
  }
  
  //for(int i=0;i<n;i++)D[i][i] = 0;
  //for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = min(D[i][j],D[i][k] + D[k][j]);

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

  return 0;
}

C++: #include<iostream>

using namespace std;

int n, M[100][100], W = 0, G = 1, B = 2;

void dijkstra () {

    int minv, d[100], color[100], i, u, v;

    for (i = 0; i < n; i++) {
        d[i] = (1 << 21);
        color[i] = W;
    }

    d[0] = 0;
    color[0] = G;

    while (1) {

        minv = (1 << 21);
        u = -1;

        for (i = 0; i < n; i++) {
            if (minv > d[i] && color[i] != B) {
                u = i;
                minv = d[i];
            }
        }

        if (u == -1) {
            break;
        }

        color[u] = B;

        for (v = 0; v < n; v++) {
            if (color[v] != B && M[u][v] != (1 << 21)) {
                if (d[v] > d[u] + M[u][v]) {
                    d[v] = d[u] + M[u][v];
                    color[v] = G;
                }
            }
        }

    }

    for (i = 0; i < n; i++) {
        cout << i << " " << (d[i] == (1 << 21) ? -1 : d[i]) << endl;
    }

}

int main () {

    int k, c, u, v, i, j;

    cin >> n;
    for (i = 0; i < n; i++) {
        for (j = 0; j < n; j++) {
            M[i][j] = (1 << 21);
        }
    }

    for (i = 0; i < n; i++) {
        cin >> u >> k;
        for (j = 0; j < k; j++) {
             cin >> v >> c;
             M[u][v] = c;
        }
    }

    dijkstra ();

    return 0;

}

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

enum state { New, Working, Done };

int main()
{
	int n;
	cin >> n;
	vector<vector<int>> am(n, vector<int>(n, -1));
	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;
			am[u][v] = c;
		}
	}

	vector<int> d(n, INT_MAX), p(n, INT_MAX);
	vector<state> status(n);
	d[0] = 0;
	p[0] = -1;
	status[0] = Working;
	while (true) {
		int minv = INT_MAX;
		int node = -1;
		for (int i = 0; i < n; i++) {
			if (status[i] != Done && d[i] < minv) {
				minv = d[i];
				node = i;
			}
		}
		if (minv == INT_MAX) break;
		status[node] = Done;
		for (int i = 0; i < n; i++) {
			if (am[node][i] != -1 && status[i] != Done && d[node] + am[node][i] < d[i]) {
				d[i] = d[node] + am[node][i];
				status[i] = Working;
			}
		}
	}

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

C++: #include<cstdio>
#include<iostream>
#define INF 200001 
 
int main(){
 int u,k,C,V,A[1000][1000],D[1000][1000],n;
  scanf("%d",&n);
   for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = INF;
  for(int i=0;i<n;i++){
      scanf("%d %d",&u,&k);    
      for(int j=0;j<k;j++){
    scanf("%d %d",&V,&C);
    D[u][V] = C;
      }    
  }
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j]= min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++)printf("%d %d\n",i,D[0][i]);
  return 0;
}