最短路径—— Dijkstra和Floyd算法java

算法介绍可以看我的数据结构专栏

import java.awt.print.Book;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Scanner;

class Main
 {
	 public static void main(String[] args)
	{
		Scanner sc =new Scanner(System.in);
		int n=sc.nextInt();
		int m=sc.nextInt();
		int[][] net=new int[n][n];
		
		for (int i = 0; i < m; i++)
		{
			net[sc.nextInt()][sc.nextInt()]=sc.nextInt();
		}
		System.out.println(floyd(net,3));

	}
	 //floyd
	 private static int floyd(int[][] net,int to)
	 {int n=net[0].length;
		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < n; j++)
			{
				if(net[i][j]==0&&i!=j)
					net[i][j]=10000000;
			}
		}
		 for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < n; j++)
			{
				for (int j2 = 0; j2 < n; j2++)
				{
					
					net[j][j2]=Math.min(net[j][j2], net[j][i]+net[i][j2]);
				}
			}
		}
		return(net[0][to]);
	 }
	//dijkstra
	private static int extracted(int[][] net,int to)
	{	
		int n=net[0].length;
		boolean[] marked =new boolean[n];
		int[]dis =new int[n];
		//初始化
		for (int i = 0; i < n; i++)
		{
			if(net[0][i]!=0) dis[i]=net[0][i];
			else dis[i]=10000000;
		}
		
		for (int i = 0; i < n-1; i++)
		{
			
			int cur=minTar(dis,marked);
			marked[cur]=true;
			if(cur==to) break;
			for (int j = 0; j < n; j++)
			{
				if(j!=cur&&net[cur][j]!=0&&dis[cur]+net[cur][j]<dis[j])
					dis[j]=dis[cur]+net[cur][j];
			}
		}
		return dis[to];
	}
	
	 private static int minTar(int[] dis, boolean[] marked)
	{
		// TODO Auto-generated method stub
		 int ret=0;int min=dis[0];
		 for (int i = 0; i < dis.length; i++)
		{
			if(!marked[i]&&dis[i]<min)
			{
				min=dis[i];
				ret=i;
			}
		}
		return ret;
	}

	
	 
 }