clc;clear;
[baseMVA, bus, gen, branch]=loadcase('caseR');
Wt=[1;2;3;4;5;6;7;8;7;6;5;4;3;2];

Nv=length(bus(:,1));                                                       %節(jié)點數量
Np=length(branch(:,1));                                                    %支路數量
b=ones(Np,4);b(:,1)=branch(:,1);b(:,2)=branch(:,2);b(:,3)=Wt;b(:,4)=1:Np;    %b包含所有支路,數量為14(n)
w=inf*ones(Np);
for i=1:Np
    x=b(i,1);y=b(i,2);
    w(x,y)=b(i,3);
end;  
DN=combntns(b(:,4),Nv-1);
x=0;y=0;T=[];tp=0;
% if b(i,4)=DN(x,y),T=[T;b(i,:)]
for k=1:length(DN(:,1))
%     clc;
    p=DN(k,:);
    for i=1:(Nv-1)
        IdxB(i)=find(b(:,4)==p(i));
    end;
    T=b(IdxB,:);
    QE=Ring(T);
    if QE==3,                                                              %如果沒有環(huán)，此圖為連通圖
        P=[];
        [baseMVA, bus, gen, branch]=loadcase('caseR');
        for j=1:(Nv-1)
            for i=1:Np
                if branch(i,1)==T(j,1) && branch(i,2)==T(j,2),P=[P;branch(i,:)];end;    
                if branch(i,2)==T(j,1) && branch(i,1)==T(j,2),P=[P;branch(i,:)];end;
            end;
         end;
         branch=P;
         savecase('caseT', baseMVA, bus, gen, branch);                            
         [baseMVA, bus, gen, branch, success, et]=runpf('caseT');
         Ploss=branch(:,14)+branch(:,16);                                          
         L=1000*0.3*3000*Ploss/10000;                                                                                               
         T(:,3)=T(:,3)+L; 
         Wzn=sum(T(:,3))
         if tp==0,Wz=Wzn;end;
         if Wzn<=Wz,Wz=Wzn;Tk=T;end;
         tp=tp+1;
    end;
end;


% 以下是畫圖程序
n=length(Tk(:,1));
w=inf*ones(n+1);
for i=1:n
  x=Tk(i,1);y=Tk(i,2);
  w(x,y)=Tk(i,3);
end;
[a,b]=mintreek(n+1,w);