【图论算法】Dijstra&BFS

选择V-S中的点加入S时用了贪心思想，即求d[]中legth最小且未被标记（未加入加入S）的点。

一点都没优化的实现：

 import java.lang.reflect.Array;

 /**
  * Created by yueli on 2018/10/14.
  */
 public class Dijkstra {
     boolean mark[]=new boolean[5];
     int v[][]={{0,10,-1,30,100}, {-1,0,50,-1,-1},{-1,-1,0,-1,10},{-1,10,20,0,60},{-1,-1,-1,-1,0}};
     class Dist{
         public int pre;
         public int length;
         public Dist(){}
         public Dist(int pre,int length){
             this.pre=pre;
             this.length=length;
         }
     }
     int maxInt=0xfffffff;
     public Dist D[]=new Dist[5];
     boolean AllMarked(){
         for(int i=0;i<mark.length;i++)
             if(!mark[i])
                 return false;
         return true;
     }
     void dijkstra(final int s){
         for(int i=0;i<5;i++) {
             D[i]=new Dist();
             D[i].pre = s;
             D[i].length = v[s][i];
             mark[i]=false;
         }
         int u=s;
         mark[s]=true;
         while (!AllMarked()){
             int min=maxInt;
             for(int i=0;i<5;i++)
                 if(!mark[i]&&D[i].length>0&&D[i].length<min){
                 min=D[i].length;
                 u=i;
                 }
             System.out.print("{+"+u+"} ");
             printD();
             if(min==maxInt)break;
             mark[u]=true;
             for(int i=0;i<5;i++)
                 if(v[u][i]>0&&(D[i].length>D[u].length+v[u][i]||D[i].length<0)){
                     D[i].length=D[u].length+v[u][i];
                     D[i].pre=u;
                 }
         }
     }
     void printD(){
         for(int i=0;i<5;i++){
             System.out.print("pre:"+D[i].pre+" length:"+D[i].length+" ");
         }
         System.out.println();
     }
     void printV(){
         for(int i=0;i<5;i++) {
             for (int j = 0; j < 5; j++)
                 System.out.print(v[i][j]+" ");
             System.out.println();
         }
     }
     public static void main(String[] args) {
         Dijkstra dijkstra=new Dijkstra();
         dijkstra.printV();
         dijkstra.dijkstra(0);
     }
 }

 void dijkstra(final int s){
        for(int i=0;i<5;i++) {
            D[i]=new Dist();
            D[i].pre = s;
            D[i].length = v[s][i];
            mark[i]=false;
        }
        int u=s;
        mark[s]=true;
        while (!AllMarked()){
            int min=maxInt;
            for(int i=0;i<5;i++)
                if(!mark[i]&&D[i].length>0&&D[i].length<min){
                min=D[i].length;
                u=i;
                }
            System.out.print("{+"+u+"} ");
            printD();
            if(min==maxInt)break;
            mark[u]=true;
            for(int i=0;i<5;i++)
                if(v[u][i]>0&&(D[i].length>D[u].length+v[u][i]||D[i].length<0)){
                    D[i].length=D[u].length+v[u][i];
                    D[i].pre=u;
                }
        }
    }

0 10 -1 30 100
-1 0 50 -1 -1
-1 -1 0 -1 10
-1 10 20 0 60
-1 -1 -1 -1 0
{+1} pre:0 length:0 pre:0 length:10 pre:0 length:-1 pre:0 length:30 pre:0 length:100
{+3} pre:0 length:0 pre:0 length:10 pre:1 length:60 pre:0 length:30 pre:0 length:100
{+2} pre:0 length:0 pre:0 length:10 pre:3 length:50 pre:0 length:30 pre:3 length:90
{+4} pre:0 length:0 pre:0 length:10 pre:3 length:50 pre:0 length:30 pre:2 length:60 

Process finished with exit code 0

#include <iostream>
#include<Queue>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
bool allMarked(bool *mark,const int n){
    for(int i=;i<n;i++){
        if(!mark[i]){
            return false;
        }
    }
    return true;
}
int getFirstUnmarked(bool* mark,const int n){
    for(int i=;i<n;i++){
        if(!mark[i]){
            return i;
        }
    }
    return -;
}
void BFS(bool d[][],const int n,int s){
    queue<int>q;
    bool *mark=new bool[n];
    q.push(s);mark[s]=;
    while(!q.empty()||!allMarked(mark,n)){
        while(!q.empty()){
            s=q.front();
            q.pop();
            cout<<s<<" ";
            for(int i=;i<n;i++){
                if(!mark[i]&&d[s][i]){
                    q.push(i);
                    mark[i]=;
                }
            }
        }
        if(!allMarked(mark,n)){
            q.push(getFirstUnmarked(mark,n));
        }
    }
}
void DFS(bool d[][],const int n,int s){
    queue<int>q;
    bool *mark=new bool[n];
}
int main(int argc, char *argv[]) {
    bool v[][]={
    {,,,,},
    {,,,,},
    {,,,,},
    {,,,,},
    {,,,,}};
    BFS(v,,);
    return ;
}