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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, ricordamaxmount : 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.  
  45.     uscita:=false; ricordamaxmount:=0;
  46.     while uscita=false do 
  47.        begin
  48.         j:=2; uscita:=true;
  49.         while j<lung do
  50.               begin
  51.                 if  (rimossi[j]<rimossi[j-1]) and (rimossi[j]<rimossi[j+1])                    
  52.                                       then
  53.                                            begin
  54.                                                 delete(rimossi,j,1);
  55.                                                 lung:=lung-1; 
  56.                                                 setLength(rimossi,lung);
  57.                                                 uscita:=false;                                          
  58.                                             end;
  59.                 for i:=1 to lung  do P[i-1]:=StrToInt(rimossi[i]);
  60.                 ANS := 0; 
  61. 				(*leftLIS[i] stores the length of longest increasing subsequence ending at index i*)
  62. 				(*rightLIS[i] stores the length of longest decreasing subsequence starting at index i*)
  63.     			len:=1; SetLength(LIS,len); LIS[0]:=P[0];
  64. 				 for i:=0 to  lung-1 do begin leftLIS[i]:=1; rightLIS[i]:=1; end;
  65. 				 (*Calculate LIS from left to right for each position*)
  66. 				 for i :=1 to lung-1 do
  67.                     begin
  68.                         ricercaUpper(Lis, P[i]);
  69.                        // if element is to be inserted in lis
  70.  
  71.                         if (id <>-1) and (id<>0)  then
  72.                                       begin
  73.                                         LIS[id] := P[i];
  74.                                         leftLIS[i]:=id+1;
  75.                                       end 
  76.                        // if element in not present in lis insert at the end
  77.                                     else
  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.                     end; 
  86.  
  87.     				 (* Calculate LIS from right to left (decreasing subsequence) for each position*)
  88.  
  89. 			len:=1; SetLength(LIS,len); LIS[0]:=P[N-1]; 
  90. 			for i :=lung-2  downto 0 do
  91.                     begin
  92.                         ricercaUpper(Lis, P[i]);
  93.  
  94.                        // if element is to be inserted in lis
  95.  
  96.                         if (id <>-1) and (id<>0)  then
  97.                                       begin
  98.                                         LIS[id] := P[i];
  99.                                         rightLIS[i]:=id+1;
  100.                                       end 
  101.                        // if element in not present in lis insert at the end
  102.                                     else
  103.                                       if id=-1 then
  104.                                       begin
  105.                                        len:=len+1;
  106.                                        SetLength(LIS,len);
  107.                                        LIS[len-1] := P[i];
  108.                                        rightLIS[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 := 0 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.                     if maxMountainLength>ricordamaxmount then ricordamaxmount:=maxMountainLength;
  125.  
  126.  
  127.                 j:=j+1;
  128.               end;              
  129.        end;     
  130.  
  131.  
  132.    ANS:= N - ricordamaxmount;  
  133.    WriteLn(ANS);
  134. end.
Success #stdin #stdout 0s 5304KB
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https://ideone.com/PhmTx2
language:
Pascal (fpc 3.0.4)
created:
4 days ago
visibility:
public

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