bzoj 1001 平面图转对偶图 最短路求图最小割

原题传送门http://www.lydsy.com/JudgeOnline/problem.php?id=1001

整理了下之前A的题

平面图可以转化成对偶图，然后（NlogN）的可以求出图的最小割（最大流）

算法合集有具体的讲解，有兴趣的可以在网上搜下或者向我要（QQ30056882）

/**************************************************************
    Problem:
    User: BLADEVIL
    Language: Pascal
    Result: Accepted
    Time: ms
    Memory: kb
****************************************************************/

//By BLADEVIL
var
    n, m                    :longint;
    pre, other, len, last   :array[..] of longint;
    l                       :longint;
    heng, shu, xie          :array[..,..] of longint;
    tot                     :longint;
    st, fin                 :longint;
    que, d                  :array[..] of longint;
    flag                    :array[..] of boolean;

procedure connect(x,y,z:longint);
begin
    inc(l);
    pre[l]:=last[x];
    last[x]:=l;
    other[l]:=y;
    len[l]:=z;
end;

procedure init;
var
    i, j                    :longint;
    min                     :longint;
begin
    read(n,m);
    for i:= to n do
        for j:= to m- do read(heng[i,j]);

    for i:= to n- do
        for j:= to m do read(shu[i,j]);

    for i:= to n- do
        for j:= to m- do read(xie[i,j]);
    min:=maxlongint;
    if (n=) or (m=) then
    begin
        for i:= to n do
            for j:= to m do
            begin
                if heng[i,j]> then if min>heng[i,j] then min:=heng[i,j];
                if shu[i,j]> then if min>shu[i,j] then min:=shu[i,j];
                if xie[i,j]> then if min>xie[i,j] then min:=xie[i,j];
            end;
        writeln(min);
        halt;
    end;
    tot:=*(m-)*(n-);
    for i:= to tot do
    if i mod = then
    begin
        if ((i mod (*(m-)))>) then
        begin
            connect(i,i+,shu[i div (*(m-))+,(i mod (*(m-))) div +]);
            connect(i+,i,shu[i div (*(m-))+,(i mod (*(m-))) div +]);
        end;
        if (i-*m+>) then
            if ((i mod (*(m-)))>) then
            begin
                connect(i,i-*m+,heng[i div (*(m-))+,(i mod (*(m-))) div ]);
                connect(i-*m+,i,heng[i div (*(m-))+,(i mod (*(m-))) div ]);
            end else
            begin
                connect(i,i-*m+,heng[i div (*(m-)),m-]);
                connect(i-*m+,i,heng[i div (*(m-)),m-]);
            end;
    end else
    begin
        connect(i,i+,xie[i div (*(m-))+,((i mod (*(m-)))+) div ]);
        connect(i+,i,xie[i div (*(m-))+,((i mod (*(m-)))+) div ]);
    end;
    st:=tot+; fin:=tot+;
    for i:= to (m-) do
    begin
        connect(st,i*,heng[,i]);
        connect(i*,st,heng[,i]);
    end;
    for i:= to (n-) do
    begin
        connect(st,i**(m-),shu[i,m]);
        connect(i**(m-),st,shu[i,m]);
    end;
    connect(st,*(m-),shu[,m]);
    connect(st,*(m-),heng[,m-]);
    connect(*(m-),st,shu[,m]);
    connect(*(m-),st,heng[,m-]);
    for i:= to (m-) do
    begin
        connect((n-)**(m-)+*i-,fin,heng[n,i]);
        connect(fin,(n-)**(m-)+*i-,heng[n,i]);
    end;
    for i:= to (n-) do
    begin
        connect(fin,(i-)**(m-)+,shu[i,]);
        connect((i-)**(m-)+,fin,shu[i,]);
    end;
    connect(fin,(n-)**(m-)+,shu[(n-),]);
    connect(fin,(n-)**(m-)+,heng[n,]);
    connect((n-)**(m-)+,fin,shu[(n-),]);
    connect((n-)**(m-)+,fin,heng[n,]);
end;

procedure main;
var
    i, j                    :longint;
    h, t                    :longint;
    cur                     :longint;
    q, p                    :longint;

begin
    que[]:=st;
    filldword(d,sizeof(d) div ,maxlongint div );
    d[st]:=;
    t:=; h:=;
    while h<>t do
    begin
        h:=h mod +;
        cur:=que[h];
        flag[cur]:=false;
        q:=last[cur];
        while q<> do
        begin
            p:=other[q];
            if d[cur]+len[q]<d[p] then
            begin
                d[p]:=d[cur]+len[q];
                if not flag[cur] then
                begin
                    t:=t mod +;
                    que[t]:=p;
                    flag[p]:=true;
                end;
            end;
            q:=pre[q];
        end;
    end;
    writeln(d[fin]);
end;    

begin
    ///assign(input,'stop.in'); reset(input);
    ///assign(output,'stop.out'); rewrite(output);
    init;
    main;
    ///close(output); close(output);
end.