高斯消元模板（pascal）

洛谷P3389评测

program rrr(input,output);
const
  eps=1e-8;
var
  a:array[0..110,0..110]of double;
  n,i,j,k:longint;
  t:double;
begin
   assign(input,'r.in');assign(output,'r.out');reset(input);rewrite(output);
   readln(n);
   for i:=1 to n do for j:=1 to n+1 do read(a[i,j]);
   for i:=1 to n do
      begin
         k:=i;
         for j:=i+1 to n do if abs(a[j,i])>abs(a[k,i]) then k:=j;
         if abs(a[k,i])<eps then begin write('No Solution');close(input);close(output);halt; end;
         for j:=i to n+1 do begin t:=a[i,j];a[i,j]:=a[k,j];a[k,j]:=t; end;
         t:=a[i,i];for j:=i to n+1 do a[i,j]:=a[i,j]/t;
         for j:=1 to n do
            if j<>i then
               begin
                  t:=a[j,i];
                  for k:=i to n+1 do a[j,k]:=a[j,k]-a[i,k]*t;
               end;
      end;
   for i:=1 to n do writeln(a[i,n+1]:0:2);
   close(input);close(output);
end.