[置顶] 最小生成树Prim算法
二话不说直接贴代码
原图传送门:http://www.tyut.edu.cn/kecheng1/site01/suanfayanshi/minispantree.asp
但是上面展现的是克鲁斯卡尔算法。我这里是普里姆算法。
#include <iostream>
#include <list>
#include <deque>
#include <algorithm>
using namespace std;
typedef struct Line
{
int Dot1;
int Dot2;
int Power;
}Line;
static const int arr[] = {0,1,6,
0,2,1,
0,3,5,
1,2,5,
1,4,3,
2,3,7,
2,4,5,
2,5,4,
3,5,2,
4,5,6
};
void BuildMap(list<Line>& vet)
{
/*do
{
Line temp;
cin>>temp.Dot1>>temp.Dot2>>temp.Power;
vet.push_back(temp);
}while(getchar() != '#');*/
for(int i = 0;i < sizeof(arr)/(sizeof(int)*3);++i)
{
Line temp;
temp.Dot1 = arr[i*3];
temp.Dot2 = arr[i*3+1];
temp.Power = arr[i*3+2];
vet.push_back(temp);
}
}
void MST(list<Line>&map,list<Line>& tree)
{
list<Line *> Open;
list<int> OpenId;
for(auto p = map.begin();p != map.end();++p)
{
Open.push_back(&*p);
if(find(OpenId.begin(),OpenId.end(),p->Dot1) == OpenId.end())
OpenId.push_back(p->Dot1);
if(find(OpenId.begin(),OpenId.end(),p->Dot2) == OpenId.end())
OpenId.push_back(p->Dot2);
}
Open.sort([](const Line* a,const Line* b){return a->Power < b->Power;});//支持C++11的编译器
tree.push_back(**Open.begin());
OpenId.erase(find(OpenId.begin(),OpenId.end(),(*Open.begin())->Dot1));
OpenId.erase(find(OpenId.begin(),OpenId.end(),(*Open.begin())->Dot2));
Open.pop_front();
auto q = Open.begin();
while(!OpenId.empty())
{
if(find(OpenId.begin(),OpenId.end(),(*q)->Dot1) == OpenId.end()
&& find(OpenId.begin(),OpenId.end(),(*q)->Dot2) == OpenId.end())
{//已加入
Open.erase(q);
q = Open.begin();
}
else if(find(OpenId.begin(),OpenId.end(),(*q)->Dot1) == OpenId.end()
|| find(OpenId.begin(),OpenId.end(),(*q)->Dot2) == OpenId.end())
{//已加入
if(find(OpenId.begin(),OpenId.end(),(*q)->Dot1) == OpenId.end())
OpenId.erase(find(OpenId.begin(),OpenId.end(),(*q)->Dot2));
else if(find(OpenId.begin(),OpenId.end(),(*q)->Dot2) == OpenId.end())
OpenId.erase(find(OpenId.begin(),OpenId.end(),(*q)->Dot1));
tree.push_back(**q);
Open.erase(q);
q = Open.begin();
}
else
{
++q;
}
}
}
int main()
{
list<Line> map;
list<Line> tree;
BuildMap(map);
MST(map,tree);
return 0;
}