高斯消元模板（pascal）
洛谷P3389评测
1 program rrr(input,output); 2 const 3 eps=1e-8; 4 var 5 a:array[0..110,0..110]of double; 6 n,i,j,k:longint; 7 t:double; 8 begin 9 assign(input,'r.in');assign(output,'r.out');reset(input);rewrite(output); 10 readln(n); 11 for i:=1 to n do for j:=1 to n+1 do read(a[i,j]); 12 for i:=1 to n do 13 begin 14 k:=i; 15 for j:=i+1 to n do if abs(a[j,i])>abs(a[k,i]) then k:=j; 16 if abs(a[k,i])<eps then begin write('No Solution');close(input);close(output);halt; end; 17 for j:=i to n+1 do begin t:=a[i,j];a[i,j]:=a[k,j];a[k,j]:=t; end; 18 t:=a[i,i];for j:=i to n+1 do a[i,j]:=a[i,j]/t; 19 for j:=1 to n do 20 if j<>i then 21 begin 22 t:=a[j,i]; 23 for k:=i to n+1 do a[j,k]:=a[j,k]-a[i,k]*t; 24 end; 25 end; 26 for i:=1 to n do writeln(a[i,n+1]:0:2); 27 close(input);close(output); 28 end.
