存費用流模板

用sfpa算出最小費用和路徑，沿這條路徑增廣

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1 const 2 inf=maxlongint; 3 var 4 n,m:longint; 5 map,a,w:array[0..120,0..120]of longint; 6 7 procedure init; 8 var 9 i,j:longint; 10 begin 11 read(m,n); 12 for i:=1 to m do 13 read(map[0,i]); 14 for i:=1 to n do 15 read(map[m+i,n+m+1]); 16 for i:=1 to m do 17 for j:=1 to n do 18 begin 19 read(w[i,m+j]); 20 w[m+j,i]:=-w[i,m+j]; 21 map[i,m+j]:=inf; 22 end; 23 end; 24 25 var 26 flag,d,dis,pre:array[0..120]of longint; 27 time:longint; 28 29 function spfa:boolean; 30 var 31 i,head,tail,num:longint; 32 begin 33 head:=1; 34 tail:=1; 35 num:=1; 36 inc(time); 37 for i:=1 to n+m+1 do 38 dis[i]:=inf; 39 dis[0]:=0; 40 d[1]:=0; 41 flag[0]:=time; 42 while num>0 do 43 begin 44 for i:=1 to n+m+1 do 45 if (a[d[head],i]>0)and(dis[d[head]]+w[d[head],i]<dis[i]) then 46 begin 47 dis[i]:=dis[d[head]]+w[d[head],i]; 48 pre[i]:=d[head]; 49 if flag[i]<>time then 50 begin 51 flag[i]:=time; 52 inc(num); 53 tail:=tail mod(n+m+1)+1; 54 d[tail]:=i; 55 end; 56 end; 57 flag[d[head]]:=time-1; 58 head:=head mod(n+m+1)+1; 59 dec(num); 60 end; 61 if dis[n+m+1]=inf then exit(false); 62 exit(true); 63 end; 64 65 procedure work; 66 var 67 i,j,aug,ans:longint; 68 begin 69 for i:=0 to n+m+1 do 70 for j:=0 to n+m+1 do 71 a[i,j]:=map[i,j]; 72 ans:=0; 73 while spfa do 74 begin 75 aug:=inf; 76 i:=n+m+1; 77 while i<>0 do 78 begin 79 j:=pre[i]; 80 if a[j,i]<aug then aug:=a[j,i]; 81 i:=j; 82 end; 83 inc(ans,dis[n+m+1]*aug); 84 i:=n+m+1; 85 while i<>0 do 86 begin 87 j:=pre[i]; 88 inc(a[i,j],aug); 89 dec(a[j,i],aug); 90 i:=j; 91 end; 92 end; 93 writeln(ans); 94 ans:=0; 95 for i:=1 to m do 96 for j:=1 to n do 97 begin 98 w[i,j+m]:=-w[i,j+m]; 99 w[j+m,i]:=-w[j+m,i]; 100 end; 101 for i:=0 to n+m+1 do 102 for j:=0 to n+m+1 do 103 a[i,j]:=map[i,j]; 104 ans:=0; 105 while spfa do 106 begin 107 aug:=inf; 108 i:=n+m+1; 109 while i<>0 do 110 begin 111 j:=pre[i]; 112 if a[j,i]<aug then aug:=a[j,i]; 113 i:=j; 114 end; 115 inc(ans,dis[n+m+1]*aug); 116 i:=n+m+1; 117 while i<>0 do 118 begin 119 j:=pre[i]; 120 inc(a[i,j],aug); 121 dec(a[j,i],aug); 122 i:=j; 123 end; 124 end; 125 writeln(-ans); 126 end; 127 128 begin 129 assign(input,'trans.in'); 130 reset(input); 131 assign(output,'trans.out'); 132 rewrite(output); 133 init; 134 work; 135 close(input); 136 close(output); 137 end. View Code

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轉(zhuǎn)載于:https://www.cnblogs.com/Randolph87/p/3602203.html

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