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  1. program mountain;(*21 punti 23 24 25 26 corretti*)
  2. Uses sysutils, Math;
  3.  
  4. const
  5.     MAXN = 100005;
  6.  
  7. Type elenco= Array of LongInt;
  8.  
  9. var
  10.     ANS, N, i, id, x, maxMountainLength, lung, len, count : LongInt;
  11.     P, leftLIS, rightLIS, valli: Array[0..MAXN-1] of LongInt;
  12.     LIS : elenco;
  13.     rimossi : Ansistring;
  14.  
  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.      count:=0;
  48.      i:=2; 
  49.  
  50.         while i<=lung do
  51.               begin
  52.                 if  (rimossi[i]<rimossi[i-1]) and (rimossi[i]<rimossi[i+1])                    
  53.                                       then
  54.                                            begin
  55.                                                 if (i+count)<lung then valli[i+count-1]:=-1;
  56.                                                 delete(rimossi,i,1);
  57.                                                 lung:=lung-1;  count:=count+1;
  58.                                                 setLength(rimossi,lung);                                                                                                                                     
  59.                                             end
  60.                                        else i:=i+1;
  61.               end; 
  62.  
  63.     ANS := 0; 
  64. 	(*leftLIS[i] stores the length of longest increasing subsequence ending at index i*)
  65. 	(*rightLIS[i] stores the length of longest decreasing subsequence starting at index i*)
  66.     len:=1; SetLength(LIS,len); LIS[0]:=P[0];
  67.     for i:=0 to  N-1 do begin leftLIS[i]:=1; rightLIS[i]:=1; end;
  68.     (*Calculate LIS from left to right for each position*)
  69.     for i :=1 to N-1 do
  70.                     begin
  71.  
  72.                            ricercaUpper(Lis, P[i]);
  73.                            // if element in not present in lis insert at the end
  74.  
  75.                            if id=-1 then
  76.                                    begin
  77.                                      len:=len+1;
  78.                                      SetLength(LIS,len);
  79.                                      LIS[len-1] := P[i];
  80.                                      leftLIS[i]:=len;
  81.                                    end
  82.                                  else
  83.                                     begin
  84.                                       // if element is to be inserted in lis
  85.                                       if ((id<>0) and (valli[id]=-1) and (valli[i]<>-1))  then
  86.                                                      begin
  87.                                                         LIS[id] := P[i];
  88.                                                         leftLIS[i]:=id+1;                                                       
  89.                                                      end
  90.                                                else 
  91.                                                 leftLIS[i]:=0;
  92.  
  93.                                     end; 
  94.  
  95.              end;      
  96.  
  97.        (* Calculate LIS from right to left (decreasing subsequence) for each position*)
  98.  
  99.    len:=1; SetLength(LIS,len); LIS[0]:=P[N-1]; 
  100.  
  101.    for i :=N-2  downto 0 do
  102.                     begin
  103.                         ricercaUpper(Lis, P[i]);
  104.                         if id=-1 then
  105.                                    begin
  106.                                      len:=len+1;
  107.                                      SetLength(LIS,len);
  108.                                      LIS[len-1] := P[i];
  109.                                      rightLIS[i]:=len;
  110.                                    end
  111.                                  else
  112.                                     begin
  113.                                       // if element is to be inserted in lis
  114.                                       if (id<>0) and (valli[N-1-id]=-1) and (valli[i]<>-1) then
  115.                                                      begin
  116.                                                         LIS[id] := P[i];
  117.                                                         rightLIS[i]:=id+1;                                                        
  118.                                                      end
  119.                                                 else  
  120.                                                    rightLIS[i]:=0;
  121.  
  122.  
  123.                                    end;                    
  124.                     end;
  125.  
  126.     maxMountainLength := 0;
  127.     (* Find the maximum length of mountain subsequence*)
  128.     // for every index check for longest mountain array,
  129.     for i := 0 to N-1 do
  130.              begin
  131.                 if (leftLIS[i] >=1) AND (rightLIS[i] >= 1) then 
  132.                       begin
  133.                         x := leftLIS[i] + rightLIS[i] - 1;
  134.                         maxMountainLength := max(maxMountainLength, x);
  135.                       end;  
  136.              end;
  137.     // returning removals
  138.  
  139.    ANS:= N - maxMountainLength; 
  140.    WriteLn(ANS);
  141. end.
Success #stdin #stdout 0s 5288KB
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https://ideone.com/8nWihe
language:
Pascal (fpc 3.0.4)
created:
4 hours ago
visibility:
public

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