noi4_6_1799[最短前缀]

字典树。数据不大，代码不短……

type knot=record
           sum:longint;
           son:array[0..30] of longint;
           ch:char;
          end;

var tree:array[1..30000] of knot;
    st:array[1..1000] of string[20];
    n,tot:longint;

procedure insert(k,len:longint);
var i:longint;
begin
 inc(tree[k].sum);
 if len>length(st[n]) then exit;
 for i:=1 to tree[k].son[0] do
  if tree[tree[k].son[i]].ch=st[n][len] then
   begin 
    insert(tree[k].son[i],len+1);
    exit;
   end;
 inc(tree[k].son[0]);
 inc(tot);
 tree[k].son[tree[k].son[0]]:=tot;
 tree[tot].sum:=0;
 tree[tot].ch:=st[n][len];
 tree[tot].son[0]:=0;
 insert(tot,len+1);
end;

procedure find(sn,k,len:longint);
var i:longint;
begin
 if k<>1 then write(tree[k].ch);
 if len>length(st[sn]) then exit;
 if tree[k].sum=1 then
   exit;
 for i:=1 to tree[k].son[0] do
  if tree[tree[k].son[i]].ch=st[sn][len] then
   find(sn,tree[k].son[i],len+1);
end;

procedure prepare;
begin
 tree[1].son[0]:=0;
 tree[1].ch:=' ';
 tree[1].sum:=0;
end;

procedure scanf;
begin
 n:=0;
 tot:=1;
 while not eoln do
  begin
   inc(n);
   readln(st[n]);
   insert(1,1);
  end;
end;

procedure printf;
var i:longint;
begin
 for i:=1 to n do
  begin
   write(st[i],' ');
   find(i,1,1);
   writeln;
  end;
end;

begin
 prepare;
 scanf;
 printf; 
end.