目测代码应该没什么问题啊= =

var

s:array [1..26*26,1..2] of longint;

n,i,j,t:longint;

m:longint;

ch1,ch2:char;

str:string;

best,total:longint;

line:array [1..200000,1..2] of longint;

link:array [1..20000] of longint;

vis:array [1..20000] of boolean;

map:array [1..20000] of longint;

function dfs(x:longint):boolean;

var

p,node:longint;

begin

p:=map[x];

vis[x]:=true;

while p-1 do

begin

node:=line[p,1];

if ( link[node]=0) or ( (not vis[link[node]]) and (dfs(link[node])) ) then

begin

link[node]:=x;

exit(true);

end;

p:=line[p,2];

end;

exit(false);

end;

procedure make(a,b:longint);

begin

inc(total);

line[total,1]:=b;

line[total,2]:=map[a];

map[a]:=total;

end;

begin

readln(m,n);best:=0;

fillchar(map,sizeof(map),$ff);

for i:=1 to n do

begin

read(str);

s:=ord(str[1])-ord('A')+1;

delete(str,1,1);

val(str,s);

readln;

end;

for i:=1 to n do

begin

if (s+s) mod 2=0 then

for j:=1 to n do

begin

if ( (abs(s-s[j,1])=1) and (abs(s-s[j,2])=2) ) or

( (abs(s-s[j,1])=2) and (abs(s-s[j,2])=1) ) then

begin

make(i,j);

end;

end;

end;

for i:=1 to n do

begin

if (s+s) mod 2=0 then

begin

fillchar(vis,sizeof(vis),false);

if dfs(i) then inc(best);

end;

end;

writeln(best);

end.

求大牛帮忙。。