【UOJ179】线性规划（单纯形）

题意：

思路：单纯形模板

var a:array[0..100,0..100]of double;
    idx,idy,q:array[0..100]of longint;
    c:array[0..100]of double;
    n,m,i,j,op,x,y:longint;
    eps,mn:double;

procedure swap(var x,y:longint);
var t:longint;
begin
 t:=x; x:=y; y:=t;
end;

procedure pivot(x,y:longint);
var i,j,tot:longint;
    tmp:double;
begin
 swap(idy[x],idx[y]);
 tmp:=a[x,y]; a[x,y]:=1/a[x,y];
 for i:=0 to n do
  if y<>i then a[x,i]:=a[x,i]/tmp;
 tot:=0;
 for i:=0 to n do
  if (i<>y)and((a[x,i]>eps)or(a[x,i]<-eps)) then
  begin
   inc(tot); q[tot]:=i;
  end;
 for i:=0 to m do
 begin
  if (x=i)or((a[i,y]<eps)and(a[i,y]>-eps)) then continue;
  for j:=1 to tot do a[i,q[j]]:=a[i,q[j]]-a[x,q[j]]*a[i,y];
  a[i,y]:=-a[i,y]/tmp;
 end;
end;

begin
 //assign(input,'uoj179.in'); reset(input);
 //assign(output,'uoj179.out'); rewrite(output);
 readln(n,m,op);
 randomize;
 eps:=1e-8;
 for i:=1 to n do read(a[0,i]);
 for i:=1 to m do
 begin
  for j:=1 to n do read(a[i,j]);
  read(a[i,0]);
 end;
 for i:=1 to n do idx[i]:=i;
 for i:=1 to m do idy[i]:=i+n;
 while true do
 begin
  x:=0; y:=0;
  for i:=1 to m do
   if (a[i,0]<-eps)and((x=0)or(random(2)=1)) then x:=i;
  if x=0 then break;
  for i:=1 to n do
   if (a[x,i]<-eps)and((y=0)or(random(2)=1)) then y:=i;
  if y=0 then
  begin
   writeln('Infeasible');
  // close(input);
   //close(output);
   exit;
  end;
  pivot(x,y);
 end;
 while true do
 begin
  x:=0; y:=0; mn:=1e15;
  for i:=1 to n do
   if a[0,i]>eps then begin y:=i; break; end;
  if y=0 then break;
  for i:=1 to m do
   if (a[i,y]>eps)and(a[i,0]/a[i,y]<mn) then
   begin
    mn:=a[i,0]/a[i,y]; x:=i;
   end;
  if x=0 then
  begin
   writeln('Unbounded');
 //  close(input);
 //  close(output);
   exit;
  end;
  pivot(x,y);
 end;
 writeln(-a[0,0]:0:8);
 if op=0 then exit;
 for i:=1 to m do
  if idy[i]<=n then c[idy[i]]:=a[i,0];
 for i:=1 to n do
 begin
  write(c[i]:0:8);
  if i<n then write(' ');
 end;

 //close(input);
 //close(output);
end.