Bzoj 3523 [Poi2014]Bricks

原题网址：http://www.lydsy.com/JudgeOnline/problem.php?id=3523
很显然的贪心，每次找不和前面元素重复的最多的，尾部颜色在数量相同时优先级更高。WA了好多发因为姿势丑，如果堆顶元素和前面元素一样只要先把堆顶拿出来就好了。。

type  rec=record        c,cnt:longint;      end;  const  MAXN=1000050;var  heap:array[0..MAXN] of rec;  a,c,cp:array[0..MAXN] of longint;  n,m,st,nd,i,cnt:longint;  t:rec;procedure swp(var a,b:longint);  var t:longint;  begin t:=a;a:=b;b:=t; end;procedure swap(a,b:longint);  begin    swp(heap[a].c,heap[b].c);    swp(heap[a].cnt,heap[b].cnt);  end;operator >(a,b:rec)c:boolean;  begin exit((a.cnt>b.cnt)or(a.cnt=b.cnt)and(a.c=nd));end;  procedure heapup(x:longint);  begin    while ((x>1)and(heap[x]>heap[x>>1])) do      begin        swap(x,x>>1);        x:=x>>1;      end;  end;procedure heapdown(x:longint);  var    e:longint;  begin    while ((x<<1<=cnt)and(heap[x<<1]>heap[x])or(x<<1+1<=cnt)and(heap[x<<1+1]>heap[x])) do      begin        e:=x<<1+ord((x<<1+1<=cnt)and(heap[x<<1+1].cnt>heap[x<<1].cnt));        swap(x,e);        x:=e;      end;  end;procedure push(x:rec);  begin    inc(cnt);    heap[cnt]:=x;    heapup(cnt);  end;procedure poop;  begin    heap[1]:=heap[cnt];    dec(cnt);    heapdown(1);  end;procedure no_solution;  begin    writeln(0);    halt;  end;begin  read(n,st,nd);m:=0;  for i:=1 to n do read(a[i]);  cp:=a;  for i:=1 to n do inc(m,a[i]);  dec(a[st]);if (a[st]<0) then no_solution;  dec(a[nd]);if (a[nd]<0) then no_solution;  for i:=1 to n do    if (a[i]>0) then      begin        t.c:=i;        t.cnt:=a[i];        push(t);      end;  c[1]:=st;c[m]:=nd;  for i:=2 to m-1 do    if (heap[1].c<>c[i-1])      then        begin          c[i]:=heap[1].c;          dec(heap[1].cnt);          if (heap[1].cnt=0)            then poop            else heapdown(1);        end      else        begin          if (cnt=1) then no_solution;          t:=heap[1];poop;          c[i]:=heap[1].c;          dec(heap[1].cnt);          if (heap[1].cnt=0)            then poop            else heapdown(1);          push(t);          end;  if (c[m]=c[m-1]) then no_solution;    for i:=1 to m-1 do    write(c[i],' ');  writeln(c[m]);end.