poj 1679 Prim 算法解决

//解析等有时间再写，欢迎关注啰
#include<iostream>
#include<vector>
#include<queue>
#include<string>
#include<sstream>
#include<set>
#include<map>
using namespace std;

int INF=65535;
int edge[110][110];
int del[110][110];
int t,n,m;
int used[110][110];
int Equal[110][110];
int first;
int lowcost[110];
int nearvex[110];

int prim()
{
int i,j;
for(i=1;i<=n;i++)
{
lowcost[i]=edge[i][1];
nearvex[i]=1;
}
lowcost[1]=-1;
int weight=0;
for(i=1;i<n;i++)
{
int v=-1;
int min=INF;
for(j=1;j<=n;j++)
{
if(lowcost[j]!=-1&&del[j][nearvex[j]]==1)
continue;
if(lowcost[j]!=-1&&lowcost[j]<min)
{
min=lowcost[j];
v=j;
}
}
if(v==-1)
return -1;
lowcost[v]=-1;
weight+=min;
if(first)
{
used[v][nearvex[v]]=1;
used[nearvex[v]][v]=1;
}
for(j=1;j<=n;j++)
{
if(lowcost[j]>edge[j][v])
{
lowcost[j]=edge[j][v];
nearvex[j]=v;
}
}
}
return weight;
}

int main()
{
while(cin>>t)
{
while(t--)
{
map<int,int> value2index;
cin>>n>>m;
int i,j;
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
edge[i][j]=INF;
used[i][j]=0;
del[j][i]=0;
Equal[i][j]=0;
}
}
vector<pair<int,int> > v[1000];
for(i=0;i<m;i++)
{
int x,y,w;
cin>>x>>y>>w;
edge[x][y]=edge[y][x]=w;
pair<int,int> temp;
temp.first=x;
temp.second=y;
v[w].push_back(temp);
}
first=1;
int sumweight1,sumweight2;
bool common=0;

for(i=0;i<1000;i++)
{
if(v[i].size()<=1)
continue;
for(j=0;j<v[i].size();j++)
{
int x=v[i][j].first;
int y=v[i][j].second;
Equal[x][y]=1;
Equal[y][x]=1;
common=1;
}
}

sumweight1=prim();
first=0;
if(common)
{
bool flag=0;
for(i=1;i<=n;i++)
{
for(j=i+1;j<=n;j++)
{
if(used[i][j]&&Equal[i][j])
{
del[i][j]=1;
del[j][i]=1;
int temp=edge[i][j];
edge[i][j]=INF;
edge[j][i]=INF;
int sumweight2=prim();
if(sumweight1==sumweight2)
{
flag=1;
break;
}
del[i][j]=0;
del[j][i]=0;
edge[i][j]=temp;
edge[j][i]=temp;
}

}
if(flag)
{
cout<<"Not Unique!"<<endl;
break;
}
}
if(!flag)
cout<<sumweight1<<endl;
}
else
{
cout<<sumweight1<<endl;
}
}
}
system("pause");
return 0;
}