1934: [Shoi2007]Vote 善意的投票

 1 /**************************************************************
 2     Problem: 1934
 3     User: HansBug
 4     Language: Pascal
 5     Result: Accepted
 6     Time:60 ms
 7     Memory:3484 kb
 8 ****************************************************************/
 9  
10 type
11     point=^node;
12     node=record
13                g,w:longint;
14                next,anti:point;
15     end;
16 var
17    i,j,k,l,m,n,ans,s,t:longint;
18    a:array[0..100000] of point;
19    c,d,dv:array[0..100000] of longint;
20 function min(x,y:longint):longint;inline;
21          begin
22               if x<y then min:=x else min:=y;
23          end;
24 procedure add(x,y,z:longint);inline;
25           var p:point;
26           begin
27                new(p);p^.g:=y;p^.w:=z;p^.next:=a[x];a[x]:=p;
28                new(p);p^.g:=x;p^.w:=0;p^.next:=a[y];a[y]:=p;
29                a[x]^.anti:=a[y];a[y]^.anti:=a[x];
30           end;
31 function dfs(x,flow:longint):longint;inline;
32          var i,j,k,l:longint;p:point;
33          begin
34               if x=t then exit(flow);
35               dfs:=0;p:=a[x];
36               while p<>nil do
37                     begin
38                          if (p^.w>0) and (d[x]=(d[p^.g]+1)) then
39                             begin
40                                  k:=dfs(p^.g,min(flow-dfs,p^.w));
41                                  dec(p^.w,k);
42                                  inc(p^.anti^.w,k);
43                                  inc(dfs,k);
44                                  if dfs=flow then exit;
45                             end;
46                          p:=p^.next;
47                     end;
48               if d[s]=n then exit;
49               dec(dv[d[x]]);
50               if dv[d[x]]=0 then d[s]:=n;
51               inc(d[x]);
52               inc(dv[d[x]]);
53          end;
54 begin
55      readln(n,m);s:=1;t:=n+2;
56      for i:=1 to n+2 do a[i]:=nil;
57      for i:=1 to n do
58          begin
59               read(c[i]);
60               if c[i]=1 then add(1,i+1,1) else add(i+1,n+2,1);
61          end;
62      readln;
63      for i:=1 to m do
64          begin
65               readln(j,k);
66               if c[j]=1 then add(j+1,k+1,1) else add(k+1,j+1,1);
67          end;
68      n:=n+2;
69      ans:=0;
70      fillchar(d,sizeof(d),0);
71      fillchar(dv,sizeof(dv),0);dv[0]:=n;
72      while d[s]<n do inc(ans,dfs(s,maxlongint));
73      writeln(ans);
74      readln;
75 end.