金粉世家金燕西婚后:求虫食算 强搜+剪枝 PASCAL

{$R-,S-,Q-,I-}
var
a,b,c:array[0..26] of char;
val:array['A'..'Z'] of integer;
use:array[0..26] of boolean;
i,j,k,n:integer;
Find:boolean;

Procedure Print;
var i:integer;
begin
for i:=0 to n-2 do write(val[chr(ord('A')+i)],' ');
writeln(val[chr(ord('A')+n-1)]);
Find:=true;
end;

Function check:boolean;
var k:integer;
begin
check:=true;
for k:=1 to n do if (val[a[k]]<>-1)and(val[b[k]]<>-1)and(val[c[k]]<>-1) then
if ((val[a[k]]+val[b[k]])mod n<>val[c[k]])
and((val[a[k]]+val[b[k]]+1) mod n<>val[c[k]]) then exit;
check:=false;
end;

Procedure Search(k,left:integer);
var i,j:integer;
cana,canb,canc:boolean;
begin
if k=0 then begin if left=0 then Print; exit; end;
if check then exit;
cana:=false; if val[a[k]]<>-1 then cana:=true;
for i:=n-1 downto 0 do if ((cana=false) and (use[i]))or((cana) and (i=val[a[k]])) then
begin
use[i]:=false; val[a[k]]:=i; canb:=false;
if val[b[k]]<>-1 then canb:=true;
for j:=n-1 downto 0 do if ((canb=false) and (use[j]))or((canb) and (j=val[b[k]])) then
begin
use[j]:=false; val[b[k]]:=j; canc:=false;
if val[c[k]]<>-1 then canc:=true;
if ((canc=false) and (use[(i+j+left) mod n]))or((canc) and ((i+j+left) mod n=val[c[k]])) then
begin
use[(i+j+left) mod n]:=false; val[c[k]]:=(i+j+left) mod n;
Search(k-1,(i+j+left) div n); if Find then exit;
if canc=false then begin use[(i+j+left) mod n]:=true; val[c[k]]:=-1; end;
end;
if canb=false then begin use[j]:=true; val[b[k]]:=-1; end;
end;
if cana=false then begin use[i]:=true; val[a[k]]:=-1; end;
end;
end;

begin
while not seekeof do
begin
readln(n);
for i:=1 to n do read(a[i]); readln;
for i:=1 to n do read(b[i]); readln;
for i:=1 to n do read(c[i]); readln;
fillchar(val,sizeof(val),byte(-1));
fillchar(use,sizeof(use),true);
Find:=false;
Search(n,0);
end;
end.
完了