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  1. program mountain;
  2. Uses sysutils, Math;
  3.  
  4. const
  5.     MAXN = 100005;
  6. Type elenco= Array of LongInt;
  7. var
  8.     ANS, N, i, j, id,x, maxMountainLength, lung, len : LongInt;
  9.     P, leftLIS, rightLIS : Array[0..MAXN-1] of LongInt;
  10.     LIS : elenco;
  11.     rimossi : Ansistring;
  12.     uscita : boolean;
  13.  
  14.  
  15. Procedure ricercaUpper (var w:elenco; target:Longint); (*ritorna indice del valore maggiore/uguale a target oppure -1 se non esiste*)
  16.   var m,start,eend: Longint;
  17.  
  18.  begin  
  19.    start:=0; eend:=len-1 ; m:=-1;
  20.    while start<=eend do
  21.            begin
  22.                   m:=(start + eend) div 2;
  23.                   if w[m]<target then  start:=m+1
  24.                                  else  if w[m]>=target then  begin id:=m;  eend:=m-1 end;
  25.            end;
  26.    if start=len then id:=-1;
  27.  
  28.  end;
  29.  
  30.  
  31.  
  32.  
  33. begin
  34.     (*assign(input,  'input.txt');  reset(input);
  35.     assign(output, 'output.txt'); rewrite(output);*)  
  36.  
  37.     ReadLn(N);
  38.     rimossi:=''; lung:=N; 
  39.     for i:=0 to N-1 do begin
  40.                         Read(P[i]);
  41.                         rimossi:=rimossi+IntTostr(P[i]);
  42.                        end;  
  43.     ReadLn();
  44.     i:=2; uscita:=false;
  45.     while uscita=false do 
  46.        begin
  47.         i:=2; uscita:=true;
  48.         while i<lung do
  49.               begin
  50.                 if  (rimossi[i]<rimossi[i-1]) and (rimossi[i]<rimossi[i+1])                    
  51.                                       then
  52.                                            begin
  53.                                                 delete(rimossi,i,1);
  54.                                                 lung:=lung-1;  
  55.                                                 uscita:=false;                                          
  56.                                             end;
  57.                 i:=i+1;
  58.               end;              
  59.        end;     
  60.     for i:=1 to lung  do P[i-1]:=StrToInt(rimossi[i]); 
  61.  
  62.     ANS := 0; 
  63. 	(*leftLIS[i] stores the length of longest increasing subsequence ending at index i*)
  64. 	(*rightLIS[i] stores the length of longest decreasing subsequence starting at index i*)
  65.     len:=1; SetLength(LIS,len); LIS[0]:=P[0];
  66.     for i:=0 to  lung-1 do begin leftLIS[i]:=1; rightLIS[i]:=1; end;
  67.     (*Calculate LIS from left to right for each position*)
  68.     for i :=1 to lung-1 do
  69.                     begin
  70.                         ricercaUpper(Lis, P[i]);
  71.                        // if element is to be inserted in lis
  72.  
  73.                         if id <>-1 then
  74.                                       begin
  75.                                         LIS[id] := P[i];
  76.                                         leftLIS[i]:=id+1;
  77.                                       end 
  78.                        // if element in not present in lis insert at the end
  79.                                     else
  80.                                       begin
  81.                                        len:=len+1;
  82.                                        SetLength(LIS,len);
  83.                                        LIS[len-1] := P[i];
  84.                                        leftLIS[i]:=len;
  85.                                       end; 
  86.                     end; 
  87.  
  88.        (* Calculate LIS from right to left (decreasing subsequence) for each position*)
  89.  
  90.    len:=1; SetLength(LIS,len); LIS[0]:=P[N-1]; 
  91.    for i :=lung-2  downto 0 do
  92.                     begin
  93.                         ricercaUpper(Lis, P[i]);
  94.  
  95.                        // if element is to be inserted in lis
  96.  
  97.                         if id <>-1 then
  98.                                       begin
  99.                                         LIS[id] := P[i];
  100.                                         leftLIS[i]:=id+1;
  101.                                       end 
  102.                        // if element in not present in lis insert at the end
  103.                                     else
  104.                                       begin
  105.                                        len:=len+1;
  106.                                        SetLength(LIS,len);
  107.                                        LIS[len] := P[i];
  108.                                        leftLIS[i]:=len;
  109.                                       end; 
  110.                     end;
  111.  
  112.     maxMountainLength := 0;
  113.     (* Find the maximum length of mountain subsequence*)
  114.     // for every index check for longest mountain array,
  115.     for i := 1 to lung-1 do
  116.              begin
  117.                 if (leftLIS[i] >= 1) AND (rightLIS[i] >= 1) then 
  118.                       begin
  119.                         x := leftLIS[i] + rightLIS[i] - 1;
  120.                         maxMountainLength := max( maxMountainLength, x);
  121.                       end;  
  122.              end;
  123.     // returning removals
  124.  
  125.    ANS:= N - maxMountainLength; 
  126.    WriteLn(ANS);
  127. end.
  128.  
Success #stdin #stdout 0s 5320KB
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https://ideone.com/Hev8wW
language:
Pascal (fpc 3.0.4)
created:
3 hours ago
visibility:
public

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