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  1. program mountain;
  2. Uses sysutils, Math;
  3.  
  4. const
  5.     MAXN = 100005;
  6.  
  7. Type elenco= Array of LongInt;
  8.  
  9. var
  10.     ANS, N, i,h, id, x, maxMountainLength, lung, len, count : LongInt;
  11.     P, leftLIS, rightLIS, valli, index : Array[0..MAXN-1] of LongInt;
  12.     LIS : elenco;
  13.     rimossi : Ansistring;
  14.     uscita : boolean;
  15.  
  16.  
  17. Procedure ricercaUpper (var w:elenco; target:Longint); (*ritorna indice del valore maggiore/uguale a target oppure -1 se non esiste*)
  18.   var m,start,eend: Longint;
  19.  
  20.  begin  
  21.    start:=0; eend:=len-1 ; m:=-1;
  22.    while start<=eend do
  23.            begin
  24.                   m:=(start + eend) div 2;
  25.                   if w[m]<target then  start:=m+1
  26.                                  else  if w[m]>=target then  begin id:=m;  eend:=m-1 end;
  27.            end;
  28.    if start=len then id:=-1;
  29.  
  30.  end;
  31.  
  32.  
  33.  
  34.  
  35. begin
  36.     (*assign(input,  'input.txt');  reset(input);
  37.     assign(output, 'output.txt'); rewrite(output);  *)
  38.  
  39.     ReadLn(N);
  40.     rimossi:=''; lung:=N;  
  41.     for i:=0 to N-1 do begin
  42.                         Read(P[i]);
  43.                         rimossi:=rimossi+IntTostr(P[i]);
  44.                         valli[i]:=0; 
  45.                        end;  
  46.     ReadLn();
  47.     uscita:=false;
  48.     while uscita=false do 
  49.        begin
  50.         i:=2; uscita:=true; count:=0;
  51.         while i<lung do
  52.               begin
  53.                 if  (rimossi[i]<rimossi[i-1]) and (rimossi[i]<rimossi[i+1])                    
  54.                                       then
  55.                                            begin
  56.                                                 valli[i+count+h-1]:=-1;
  57.                                                 delete(rimossi,i,1);
  58.                                                 lung:=lung-1;  count:=count+1;
  59.                                                 setLength(rimossi,lung);
  60.                                                 uscita:=false;                                          
  61.                                             end;
  62.                 i:=i+1;
  63.               end; 
  64.            h:=h+1;   
  65.        end;     
  66.  
  67.     ANS := 0; 
  68. 	(*leftLIS[i] stores the length of longest increasing subsequence ending at index i*)
  69. 	(*rightLIS[i] stores the length of longest decreasing subsequence starting at index i*)
  70.     len:=1; SetLength(LIS,len); LIS[0]:=P[0];
  71.     for i:=0 to  N-1 do begin leftLIS[i]:=1; rightLIS[i]:=1; end;
  72.     (*Calculate LIS from left to right for each position*)
  73.     for i :=1 to N-1 do
  74.                     begin
  75.                         ricercaUpper(Lis, P[i]);
  76.                        // if element in not present in lis insert at the end
  77.  
  78.                         if id=-1 then
  79.                                    begin
  80.                                      len:=len+1;
  81.                                      SetLength(LIS,len);
  82.                                      LIS[len-1] := P[i];
  83.                                       leftLIS[i]:=len;
  84.                                    end
  85.                                  else
  86.                                     begin
  87.                                       // if element is to be inserted in lis
  88.                                       if (id<>0) and (valli[id]=-1) then
  89.                                                      begin
  90.                                                         LIS[id] := P[i];
  91.                                                         leftLIS[i]:=id+1;
  92.  
  93.                                                      end
  94.  
  95.  
  96.                                 end;                    
  97.                     end; 
  98.  
  99.        (* Calculate LIS from right to left (decreasing subsequence) for each position*)
  100.  
  101.    len:=1; SetLength(LIS,len); LIS[0]:=P[N-1]; 
  102.  
  103.    for i :=N-2  downto 0 do
  104.                     begin
  105.                         ricercaUpper(Lis, P[i]);
  106.                         if id=-1 then
  107.                                    begin
  108.                                      len:=len+1;
  109.                                      SetLength(LIS,len);
  110.                                      LIS[len-1] := P[i];
  111.                                       rightLIS[i]:=len;
  112.                                    end
  113.                                  else
  114.                                     begin
  115.                                       // if element is to be inserted in lis
  116.                                       if (id<>0) and (valli[id]=-1) then
  117.                                                      begin
  118.                                                         LIS[id] := P[i];
  119.                                                         rightLIS[i]:=id+1;
  120.  
  121.                                                      end
  122.  
  123.  
  124.                                    end;                    
  125.                     end;
  126.  
  127.     maxMountainLength := 0;
  128.     (* Find the maximum length of mountain subsequence*)
  129.     // for every index check for longest mountain array,
  130.     for i := 0 to N-1 do
  131.              begin
  132.                 if (leftLIS[i] >=1) AND (rightLIS[i] >= 1) then 
  133.                       begin
  134.                         x := leftLIS[i] + rightLIS[i] - 1;
  135.                         maxMountainLength := max(maxMountainLength, x);
  136.                       end;  
  137.              end;
  138.     // returning removals
  139.  
  140.    ANS:= N - maxMountainLength; 
  141.    WriteLn(ANS);
  142. end.
Success #stdin #stdout 0s 5312KB
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https://ideone.com/eECU4L
language:
Pascal (fpc 3.0.4)
created:
1 day ago
visibility:
public

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