jaypee.h/primWithpriority.cpp at master · Jaype-e/jaypee.h · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
#include <iostream>
#include <vector>
#include <cstdlib>
#include <string>
#include <stdexcept>
#include <typeinfo>
#define F first
#define S second

using namespace std;

template < class T >
class PriorityQueue{
   private:
      vector< T > elems;     // elements

   public:
      void push(T n);
      T pop();
      bool isEmpty();
};

template < class T >
void PriorityQueue< T >::push (T n) {

        elems.push_back(n);
        int j=elems.size()-1;
        T k;
         while(j>0)
        {
      	    if(elems[(j-1)/2].F>elems[j].F)
			 	  {
			 			k=elems[j];
			 			elems[j]=elems[(j-1)/2];
			 			elems[(j-1)/2]=k;
		     		}
			 		j=(j-1)/2;
			}

}

template < class T >
bool PriorityQueue< T >::isEmpty () {
     if(elems.size()==0)
     return true;
     return false;
}

template < class T >
T PriorityQueue< T >::pop () {

        T temp,res;
        int i,j;
        j=elems.size()-1;
        res=elems[0];
        temp=elems[0];
        elems[0]=elems[j];
        elems[j]=temp;
        i=0;
        while(i<j/2){
        	if(2*i+2<j){
        		if(elems[i].F > elems[2*i+1].F && elems[i].F > elems[2*i+2].F ){
                    if( elems[2*i+1].F <= elems[2*i+2].F){
								  temp=elems[i];
        						  elems[i]=elems[2*i+1];
        						  elems[2*i+1]=temp;
        						  i=2*i+1;
                    }
                    else{
                    		temp=elems[i];
        						elems[i]=elems[2*i+2];
        						elems[2*i+2]=temp;
        						i=2*i+2;
                    }
        		}
        		else if(elems[i].F > elems[2*i+2].F ){
        				  temp=elems[i];
        				  elems[i]=elems[2*i+2];
        				  elems[2*i+2]=temp;
        				  i=2*i+2;
        		}
        		else if(elems[i].F > elems[2*i+1].F ){
        				  temp=elems[i];
        				  elems[i]=elems[2*i+1];
        				  elems[2*i+1]=temp;
        				  i=2*i+1;
        		}
        		else
        		    break;
        }
        else if(2*i+1<j){
        	 if(elems[i].F > elems[2*i+1].F ){
        				  temp=elems[i];
        				  elems[i]=elems[2*i+1];
        				  elems[2*i+1]=temp;
        				  i=2*i+1;
        		}
        		else
        		    break;
        }
        else
                break;
    }
    elems.pop_back();
    return res ;

}

vector < pair<int,int> > v[100];

void prim(int n){
	int i,j,k;
	bool isVisited[n+1]={false};
	PriorityQueue < pair< int,pair< int,int > > > A;
   pair< int,pair < int,int > > temp;

   A.push(make_pair(0,make_pair(1,1)));

   while( !A.isEmpty()){
        temp=A.pop();

        if( !isVisited[temp.S.S]){
        	   cout<<temp.S.F<<" "<<temp.S.S<<endl; //in minimum spanning tree

        	   isVisited[temp.S.S]=true;
				for(i=0;i<v[temp.S.S].size();i++){

					if( !isVisited[v[temp.S.S][i].F] )
				     A.push( make_pair( v[temp.S.S][i].S, make_pair(temp.S.S,v[temp.S.S][i].F ) ) );
				}
        }

   }

}


int main() {
		int n,i,j,m,k,a,b,w;
		cin>>n>>m;
		for(i=0;i<m;i++){
			cin>>a>>b>>w;
			v[a].push_back( make_pair(b,w));
			v[b].push_back( make_pair(a,w));
		}
	   prim(n);
}