POJ Optimal Milking 2012-08-28

Posted 2020-06-17

  1 Program poj2112;
  2 
  3 var n,c,m,mid,s,t:longint;
  4 
  5     map,a:array[1..300,1..300]of longint;
  6 
  7     cur,dis:array[1..300]of longint;
  8 
  9     vh:array[0..300]of longint;
 10 
 11  Procedure init;
 12 
 13  var i,j,k:longint;
 14 
 15   begin
 16 
 17      readln(n,c,m);
 18 
 19      for i:=1 to n+c do
 20 
 21       for j:=1 to n+c do
 22 
 23        read(map[i,j]);
 24 
 25      s:=n+c+1;t:=n+c+2;
 26 
 27   end;
 28 
 29 
 30  Procedure floyed;
 31 
 32  var i,j,k:longint;
 33 
 34   begin
 35 
 36      for k:=1 to n+c do
 37 
 38       for i:=1 to n+c do
 39 
 40        for j:=1 to n+c do
 41 
 42         if (i<>j)and(i<>k)and(j<>k)and(map[i,k]<>0)and(map[k,j]<>0) then
 43 
 44           begin
 45 
 46             if (map[i,j]=0)or(map[i,k]+map[k,j]<map[i,j]) then map[i,j]:=map[i,k]+map[k,j];
 47 
 48           end;
 49 
 50   end;
 51 
 52 
 53  Function min(a,b:longint):longint;
 54 
 55   begin
 56 
 57     if a<b then min:=a else min:=b;
 58 
 59   end;
 60 
 61 
 62  Function aug(x,nf:longint):longint;
 63 
 64  var i,j,d,l,minh,ins:longint;
 65 
 66   begin
 67 
 68     if x=t then exit(nf);
 69 
 70     l:=nf;
 71 
 72     for i:=cur[x] to t do
 73 
 74      if (a[x,i]>0)and(dis[x]=dis[i]+1) then
 75 
 76       begin
 77 
 78          cur[x]:=i;
 79 
 80          d:=aug(i,min(l,a[x,i]));
 81 
 82          dec(a[x,i],d);
 83 
 84          inc(a[i,x],d);
 85 
 86          dec(l,d);
 87 
 88          if (dis[s]=t)or(l=0) then exit(nf-l);
 89 
 90       end;
 91 
 92     if nf=l then
 93 
 94      begin
 95 
 96        minh:=t;
 97 
 98        for i:=1 to t do
 99 
100         if (a[x,i]>0)and(dis[i]<minh) then
101 
102          begin
103 
104              minh:=dis[i];ins:=i;
105 
106          end;
107 
108        cur[x]:=ins;
109 
110        dec(vh[dis[x]]);
111 
112        if vh[dis[x]]=0 then dis[s]:=t;
113 
114        dis[x]:=minh+1;
115 
116        inc(vh[dis[x]]);
117 
118      end;
119 
120     aug:=nf-l;
121 
122   end;
123 
124 
125  Function flow:longint;
126 
127  var i,j,k:longint;
128 
129   begin
130 
131      flow:=0;
132 
133      fillchar(vh,sizeof(vh),0);
134 
135      vh[0]:=t;
136 
137      fillchar(dis,sizeof(dis),0);
138 
139      for i:=1 to t do cur[i]:=1;
140 
141      fillchar(a,sizeof(a),0);
142 
143      for i:=1 to n do
144 
145       for j:=n+1 to n+c do
146 
147         if (map[i,j]<>0)and(map[i,j]<=mid) then a[i,j]:=1;
148 
149      for i:=1 to n do a[s,i]:=m;
150 
151      for i:=n+1 to n+c do a[i,t]:=1;
152 
153      while dis[s]<t do inc(flow,aug(s,maxlongint));
154 
155   end;
156 
157 
158  Procedure main;
159 
160  var i,j,k,lc,rc,ans:longint;
161 
162   begin
163 
164      floyed;
165 
166      lc:=0;rc:=200000;
167 
168      ans:=0;
169 
170      while lc<rc-1 do
171 
172       begin
173 
174          mid:=(lc+rc)div 2;
175 
176          if flow=c then begin rc:=mid;ans:=mid;end
177 
178                    else lc:=mid;
179 
180       end;
181 
182      writeln(ans);
183 
184   end;
185 
186 
187 Begin
188 
189    assign(input,‘input.in‘);assign(output,‘output.out‘);
190 
191    reset(input);rewrite(output);
192 
193       init;
194 
195       main;
196 
197    close(input);close(output);
198 
199 end.