poj3693

  1 var h,ans,y,x,sum,rank,sa:array[0..100010] of longint;
  2     f:array[0..100010,0..20] of longint;
  3     d:array[0..20] of longint;
  4     b,e,p,te,i,j,max,t,l,n,m:longint;
  5     s:ansistring;
  6 
  7 function cmp(a,b,j:longint):boolean; //注意这里排序判断要这么写（因为多测）
  8   begin
  9     if y[a]<>y[b] then exit(true);
 10     if (a+j<=n) and (b+j<=n) and (y[a+j]<>y[b+j]) then exit(true);
 11     if (a+j<=n) and (b+j<=n) then exit(false)
 12     else exit(true);
 13   end;
 14 
 15 procedure swap(var a,b:longint);
 16   var c:longint;
 17   begin
 18     c:=a;
 19     a:=b;
 20     b:=c;
 21   end;
 22 
 23 function min(a,b:longint):longint;
 24   begin
 25     if a>b then exit(b) else exit(a);
 26   end;
 27 
 28 procedure suffix;
 29   var i,j,p,m:longint;
 30   begin
 31     fillchar(sum,sizeof(sum),0);
 32     m:=255;
 33     for i:=1 to n do
 34     begin
 35       y[i]:=ord(s[i]);
 36       inc(sum[y[i]]);
 37     end;
 38     for i:=2 to m do
 39       inc(sum[i],sum[i-1]);
 40     for i:=n downto 1 do
 41     begin
 42       sa[sum[y[i]]]:=i;
 43       dec(sum[y[i]]);
 44     end;
 45     p:=1;
 46     rank[sa[1]]:=1;
 47     for i:=2 to n do
 48     begin
 49       if y[sa[i]]<>y[sa[i-1]] then inc(p);
 50       rank[sa[i]]:=p;
 51     end;
 52     m:=p;
 53     j:=1;
 54     while m<n do
 55     begin
 56       fillchar(sum,sizeof(sum),0);
 57       y:=rank;
 58       p:=0;
 59       for i:=n-j+1 to n do
 60       begin
 61         inc(p);
 62         x[p]:=i;
 63       end;
 64       for i:=1 to n do
 65         if sa[i]>j then
 66         begin
 67           inc(p);
 68           x[p]:=sa[i]-j;
 69         end;
 70 
 71       for i:=1 to n do
 72       begin
 73         rank[i]:=y[x[i]];
 74         inc(sum[rank[i]]);
 75       end;
 76       for i:=1 to m do
 77         inc(sum[i],sum[i-1]);
 78       for i:=n downto 1 do
 79       begin
 80         sa[sum[rank[i]]]:=x[i];
 81         dec(sum[rank[i]]);
 82       end;
 83       p:=1;
 84       rank[sa[1]]:=1;
 85       for i:=2 to n do
 86       begin
 87         if cmp(sa[i],sa[i-1],j) then inc(p);
 88         rank[sa[i]]:=p;
 89       end;
 90       m:=p;
 91       j:=j shl 1;
 92     end;
 93     p:=0;
 94     for i:=1 to n do
 95     begin
 96       if rank[i]=1 then continue;
 97       j:=sa[rank[i]-1];
 98       while (i+p<=n) and (j+p<=n) and (s[i+p]=s[j+p]) do inc(p);
 99       h[rank[i]]:=p;
100       if p>0 then dec(p);
101     end;
102   end;
103 
104 procedure rmq;
105   var i,j,t:longint;
106   begin
107     t:=trunc(ln(n)/ln(2));
108     d[0]:=1;
109     for i:=1 to t do
110       d[i]:=d[i-1]*2;
111     for i:=1 to n do
112       f[i,0]:=h[i];
113     for j:=1 to t do
114       for i:=1 to n do
115         if i+d[j]-1<=n then
116           f[i,j]:=min(f[i,j-1],f[i+d[j-1],j-1])
117         else break;
118   end;
119 
120 function ask(x,y:longint):longint;
121   var k:longint;
122   begin
123     if x>y then swap(x,y);
124     inc(x);
125     k:=trunc(ln(y-x+1)/ln(2));
126     exit(min(f[x,k],f[y-d[k]+1,k]));
127   end;
128 
129 begin
130   while true do
131   begin
132     inc(te);
133     readln(s);
134     if s=‘#‘ then break;
135     n:=length(s);
136     suffix;
137     rmq;
138     max:=1;
139     ans[1]:=0;
140     t:=1;
141     for l:=1 to n do
142     begin
143       i:=1;
144       while i+l<=n do
145       begin
146         p:=ask(rank[i],rank[i+l]);
147         m:=p div l+1;
148         j:=i-(l-p mod l); //判断是否能再向前延伸
149         if (j>0) and (p mod l<>0) then
150         begin
151           if ask(rank[j],rank[j+l])>=p then
152             inc(m);
153         end;
154         if m>max then
155         begin
156           max:=m;
157           t:=1;
158           ans[1]:=l;
159         end
160         else if (m=max) and (ans[t]<>l) then
161         begin
162           inc(t);
163           ans[t]:=l;
164         end;
165         i:=i+l;
166       end;
167     end;
168     b:=0; e:=0;
169     for i:=1 to n do
170     begin
171       for j:=1 to t do
172         if (sa[i]+ans[j]<=n) and (sa[i]+max*ans[j]-1<=n) and (ask(i,rank[sa[i]+ans[j]])>=(max-1)*ans[j]) then
173         begin
174           b:=sa[i];
175           e:=b+max*ans[j]-1;
176           break;
177         end;
178 
179       if b<>0 then break;
180     end;
181     write(‘Case ‘,te,‘: ‘);
182     for i:=b to e do
183       write(s[i]);
184     writeln;
185   end;
186 end.