Pelatihan OSK Algoritmika (1)

8/19/2019 Pelatihan OSK Algoritmika (1)

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algoritmika

Pelatihan OSK 2015

Rakha Kanz Kautsar

February 9, 2015

0



review pascal



basic structure

program x;

var

{Deklarasi variabel}

i,j,k : integer;

const

{Deklarasi konstanta}

PI = 3.1415;

procedure p(str:ansistring);

begin

{Isi prosedur}

end;

function f(x:integer):integer;

begin

{Isi fungsi}

end;

begin

{Isi program utama}

end.

2



conditional

if {conditional} then begin{do something}

end;

3



conditional

if {conditional} then begin

{do something}end else begin

{do something else}

end;

4



conditional

if {conditional} then begin

{do something}

end else if {another conditional} then begin{do something else}

end else begin

{if all fails, do something}

end;

5



loop

while {conditional} do begin{do something while true}

end;

6



loop

repeat{do something until true}

until {conditional};

7



loop

for {variable}:={begin value}

to {end value} do begin

{do something with the variable}

end;

8



loop

for i:=1 to 10 do begin

writeln(i);

end;

for i:=10 downto 1 do begin

writeln(i);

end;

9



contoh soal

Apa keluaran dari program berikut?

p:=true;

q:=false;

if (p=false or 3 mod 2 = 1) and (q=true and 1=1) then

writeln(’A’)else

writeln(’B’);

end;

10



contoh soal

Apa keluaran dari program berikut?

n:=3;

for i:=1 to n do begin

for j:=1 to j do begin

if(i<j) then write(’.’)else write(’#’);

end;

writeln;

end;

10



tipe data

Tipe Range

byte ..

shortint -..

smallint -....word ...

integer smallint or longint

cardinal longword

longint -..int -..

qword ..

11



beberapa algoritma penting

s g



swapping

procedure swap(var x,y:integer);

var tmp;

begintmp:=x;

x:=y;

y:=x;

end;

13

swapping



swapping

procedure swap(var x,y:integer);

begin

x:=x+y;

y:=x-y;

x:=x-y;

end;

13



euclidean algorithm



euclidean algorithm

gcd(a,b) =

a, if b = 0.

gcd(b,a mod b), otherwise.

14

euclidean algorithm



euclidean algorithm

function gcd(a,b:integer):integer;

beginif b=0 then gcd:=a

else gcd:=gcd(b,a mod b);

end;

14

sieve of eratosthenes



sieve of eratosthenes

// p adalah array [1..MAX] of boolean

// berisi default true.

for i:=2 to MAX do beginif p[i] then

for j:=i*i to MAX do p[j]:=false;

end;

// i bilangan prima iff p[i]=true.

15

fast exponentiation



fast exponentiation

be =

1,

if e

= 0b

e

2 · be

2 , if even.

b · be−1, if odd.

16

fast exponentiation



fast exponentiation

function pangkat(b,e:integer):longint;var

tmp:longint;

begin

if e=0 then pangkat:=1else if (e mod 2 = 1) then

pangkat:=b*pangkat(e-1)

else begin

tmp:=pangkat(e div 2);pangkat:=tmp*tmp;

end;

end;

16

fast exponentiation



fast exponentiation

function pangkat(b,e:longint):longint;var

res:longint;

begin

while e>0 do beginif (e mod 2 = 1) then

res *= b;

e := e div 2;

b := b * b;end;

pangkat := res;

end; 16

flood fill (dfs)



flood fill (dfs)

procedure dfs(x,y:integer);

begin

if safe(x,y) then begin

visited[x,y]:=true;

// Process..

dfs(x,y+1);

dfs(x,y-1);

dfs(x+1,y);

dfs(x-1,y);

end;

end;

17



rekursi

factorial



function factorial(x:integer):longint;

beginif x<2 then factorial:=x

else factorial:= x * factorial(x-1);

end;

19

fibonacci



function fib(n:integer):longint;

beginif n<2 then fib:=1

else fib:=fib(n-1)-fib(n-2);

end;

20

struktur umum



function f(parameter):return_value;

beginif ... then f:=base_case

else f:= f() //recurse ;

end;

21

approach



function sikat(x,y:longint):longint;

begin

if (x>=y) then sikat:=x

else sikat:=3*sikat(x+1,y)+2*sikat(x,y-1);end;

22

approach




begin



1. Pohon Faktor

22

approach




begin



1. Pohon Faktor

2. Tabel DP

22

approach




begin



1. Pohon Faktor

2. Tabel DP

3. Khusus

22

approach



vardata :

array[1..10] of integer =

(3,9,2,6,1,4,7,8,5,10);

procedure kambing(m : integer);

begin

if (m<=10) then

begin

kambing(m*2);

write(data[m],’ ’);

kambing(m*2+1);

end;

end;

Hasil pemanggilan kambing(1) adalah...23



sorting

bubble sort



swapped:=true;

repeat

swapped:=false;


if A[i]>A[i-1] then begin

swap(A[i],A[i-1]);

swapped:=true;

end;

end;n:=n-1;

until swapped=false;

25

selection sort




idx_min:=i;

for j:=i+1 to n do begin

if A[j]<A[idx_min] then

idx_min:=j;

end;

swap(A[i],A[idx_min]);

end;

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insertion sort




for j:=i downto 2 do begin

if A[j]>A[j-1] then break

else swap(A[j],A[j-1]);

end;

end;

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and other sort



∙ Merge Sort

28

and other sort



∙ Merge Sort

∙ Heap Sort

28

and other sort



∙ Merge Sort

∙ Heap Sort

∙ Quick Sort

28

and other sort



∙ Merge Sort

∙ Heap Sort

∙ Quick Sort

∙ Topological Sort

28



fin.

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Pelatihan OSK Algoritmika (1)

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