排序算法学习程序

program sort;
uses crt;
label 1,2;
type
arr=array[0..100] of integer;
var choose1,choose2,n,i,counter,cou:integer;
    a:array[0..100]of integer;
procedure selectionsort(a:array of integer);
 var i,j,k,t,r,counter:integer;
 begin
  counter:=0;
  for i:=1 to n-1 do
   begin
    k:=i;
    for j:=i+1 to n do
     if a[j]<a[k] then k:=j;
    if k<>i then
     begin
      inc(counter);
      t:=a[i];
      a[i]:=a[k];
      a[k]:=t;
      write(‘第‘,counter,‘次交换‘);
     for r:=1 to n do
       write(a[r],‘ ‘);
      readln;
     end;
   end;
 writeln(‘排序完毕!‘);
 readln;
 end;

procedure bubblesort(a:array of integer);
 var i,j,k,t,r,counter:integer;
 begin
 counter:=0;
 for i:=1 to n-1 do
   for j:=n downto i+1 do
    if a[j-1]>a[j] then
     begin
      inc(counter);
      t:=a[j-1];
      a[j-1]:=a[j];
      a[j]:=t;
      write(‘第‘,counter,‘次交换:‘);
      for r:=1 to n do
      write(a[r],‘ ‘);
      readln;
     end;
 writeln(‘排序完毕!‘);
 readln;
 end;

procedure insertionsort(a:array of integer);
 var i,j,k,t,r,counter:integer;
 begin
 counter:=0;
 for i:=2 to n do
  begin
   k:=a[i];
   j:=i-1;
   while (k<a[j]) and (j>0) do
    begin
       a[j+1]:=a[j];
       j:=j-1
    end;
   a[j+1]:=k;
   inc(counter);
   write(‘第‘,counter,‘轮:‘);
   for r:=1 to n do
     write(a[r],‘ ‘);
   readln;
  end;
  writeln(‘排序完毕!‘);
  readln;
 end;

procedure qsort(var d:arr;head,tail:longint);
var
   x,i,j,r:longint;
begin
   x:=d[head];  i:=head;  j:=tail;
   while i<j do
   begin
      while(i<j)and(d[j]>=x)do j:=j-1;
      d[i]:=d[j];
      while(i<j)and(d[i]<=x)do i:=i+1;
      d[j]:=d[i];
   end;
   d[i]:=x;
   inc(cou);
   write(‘第‘,cou,‘轮:‘);
   for r:=1 to n do write(a[r],‘ ‘);
   writeln;
   writeln(‘a[‘,i,‘]=‘,x,‘将区间[‘,head,‘,‘,tail,‘]分割成两个部分‘,‘,该数前面的数比它小,后面的数比它大.‘);
   readln;
   if head<j-1 then qsort(d,head,j-1);
   if i+1<tail then qsort(d,i+1,tail);
end;


begin
  randomize;
1:
  textcolor(white);
  writeln(‘   简单排序算法学习软件‘);
  textcolor(Green);
  writeln(‘请选择排序算法学习:‘);
  writeln(‘=========================‘);
  writeln(‘1.选择排序(SelectionSort)‘);
  writeln(‘2.冒泡排序(BubbleSort)‘);
  writeln(‘3.插入排序(InsertionSort)‘);
  writeln(‘4.快速排序(QuickSort)‘);
  writeln(‘=========================‘);
  writeln(‘5.关于作者‘);
  writeln(‘0.退出‘);
  writeln(‘==========‘);
     write(‘请选择:‘);
  repeat
     readln(choose1);
     writeln;
     if choose1=0 then halt;
     if choose1=5 then begin
          clrscr;
          writeln(‘作者:崔晨‘);
          writeln;
          writeln(‘莒县第一中学2013级7班‘);
          writeln;
          writeln(‘本程序为参赛作品,由崔晨独立编写;‘);
          writeln;
          writeln(‘其中参考了一些书籍或网络上关于排序算法的代码和相关描述;‘);
          writeln;
          writeln(‘程序主体部分为作者原创,排序算法的演示更是创新;‘);
          writeln;
          writeln(‘本程序采用FreePascal2.0.4编写,程序代码部分共410行;‘);
          writeln;
          writeln(‘如有建议欢迎批评指正.‘);
          readln;
          clrscr;
          goto 1;
       end;
     if (choose1<>1)and(choose1<>2)and(choose1<>3)and(choose1<>4)and(choose1<>5) then write(‘输入有误,请重新输入:‘);
  until (choose1=1)or(choose1=2)or(choose1=3)or(choose1=4)or(choose1=5);
  clrscr;
2:
    textcolor(white);
    case choose1 of
      1:write(‘  选择排序‘);
      2:write(‘  冒泡排序‘);
      3:write(‘  插入排序‘);
      4:write(‘  快速排序‘);
    end;
    writeln(‘学习‘);
    textcolor(green);
    writeln(‘1.程序模拟演示‘);
    writeln(‘2.算法描述‘);
    writeln(‘3.查看示例代码‘);
    writeln(‘0.返回主菜单‘);
    writeln(‘请选择:‘);
    repeat
    readln(choose2);
    if (choose2<>1)and(choose2<>2)and(choose2<>3)and(choose2<>0) then write(‘输入有误,请重新输入:‘);
  until (choose2=1)or(choose2=2)or(choose2=3)or(choose2=0);
  if choose1=1 then
   begin
     clrscr;
     if choose2=2 then
      begin
       writeln(‘(1)设数组a存放数据;‘);
       writeln;
       writeln(‘(2)在1~n中选择值最小的元素,与第1位置元素交换;‘);
       writeln;
       writeln(‘(3)在2~n中选择值最小的元素,与第2位置元素交换......‘);
       writeln;
       writeln(‘(4)直到第n-1元素与第n个元素比较排序为止‘);
       writeln;
       writeln;
       writeln(‘程序实现方法:用两重循环完成算法,外重循环i控制当前序列最小值存放的数组位置,‘);
       writeln(‘             内循环j控制i+1到n序列中选择最小的元素所在位置k.‘);
       writeln;
       writeln(‘算法时间复杂度为O(n^2)‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=3 then
      begin
       writeln(‘var a:array[0..1000] of longint;‘);
       writeln(‘    i,j,k,t:integer;‘);
       writeln(‘begin‘);
       writeln(‘ readln(n);‘);
       writeln(‘ for i:= 1 to n do read(a[i]);‘);
       writeln(‘ for i:=1 to n-1 do‘);
       writeln(‘  begin‘);
       writeln(‘   k:=i;‘);
       writeln(‘   for j:=i+1 to n do‘);
       writeln(‘    if a[j]<a[k] then k:=j;‘);
       writeln(‘   if k<>i then‘);
       writeln(‘    begin t:=a[i];a[i]:=a[k];a[k]:=t;end;‘);
       writeln(‘  end;‘);
       writeln(‘ for i:= 1 to n do write(a[i]:6);‘);
       writeln(‘ end.‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=1 then
      begin
       writeln(‘请输入演示数据的个数(系统将随机产生数据),建议不超过15:‘);
       readln(n);
       for i:=1 to n do
         a[i]:=random(1000);
       write(‘未排序前:‘);
       for i:=1 to n do
         write(a[i],‘ ‘);
       writeln;
       selectionsort(a);
       clrscr;
       goto 2;
      end;
    end;
  if choose1=2 then
    begin
     clrscr;
     if choose2=2 then
      begin
       writeln(‘(1)设数组a存放数据;‘);
       writeln;
       writeln(‘(2)对尚未排序的各元素从头到尾依次比较相邻的两个元素是否逆序(与预排顺序相反),‘);
       writeln(‘   若逆序就交换这两个元素;‘);
       writeln;
       writeln(‘(3)经过第一轮比较后便可把最大(或最小)的元素排好;‘);
       writeln;
       writeln(‘(4)用同样的办法把剩下的元素逐个比较,如果有n个元素,‘);
       writeln(‘   那么一定要进行n-1轮比较,就得到了所需要的排序.‘);
       writeln;
       writeln(‘程序实现方法:用两重循环完成算法,外重循环i控制每轮要进行多少次的比较,‘);
       writeln(‘             第一轮比较n-1次,第二轮n-2次......最后一轮比较一次.‘);
       writeln(‘             内重循环j控制每轮i次比较相邻两个元素是否逆序,若逆序就交换这两个元素‘);
       writeln;
       writeln(‘算法时间复杂度为O(n^2)‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=3 then
      begin
       writeln(‘var a:array[0..1000] of integer;‘);
       writeln(‘    i,j,k,t:integer;‘);
       writeln(‘begin‘);
       writeln(‘readln(n);‘);
       writeln(‘ for i:= 1 to n do read(a[i]);‘);
       writeln(‘ for i:=1 to n-1 do‘);
       writeln(‘      for j:=1 to n-i do‘);
       writeln(‘       if a[j]>a[j+1] then‘);
       writeln(‘        begin t:=a[j+1];a[j+1]:=a[j];a[j]:=t; end;‘);
       writeln(‘ for i:= 1 to n do write(a[i]:6);‘);
       writeln(‘ end.‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=1 then
      begin
       writeln(‘请输入演示数据的个数(系统将随机产生数据),建议不超过15:‘);
       readln(n);
       for i:=1 to n do
         a[i]:=random(1000);
       write(‘未排序前:‘);
       for i:=1 to n do
         write(a[i],‘ ‘);
       writeln;
       bubblesort(a);
       clrscr;
       goto 2;
      end;
    end;
 if choose1=3 then
   begin
     clrscr;
     if choose2=2 then
      begin
       writeln(‘(1)设数组a存放数据;‘);
       writeln;
       writeln(‘(2)从第2个数开始,取出当前数作为待排序数,逐个与前面的数比较,‘);
       writeln(‘   若小于前面的数,则前面数后移,当大于等于前面数时,插入当前空出的位置.‘);
       writeln;
       writeln(‘(3)直到第n个数插入到正确位置为止.‘);
       writeln;
       writeln;
       writeln(‘程序实现方法:用两重循环完成算法,外重循环i控制待排数字序数,‘);
       writeln(‘             从第2个数到第n个数,内重循环j控制插入的位置,‘);
       writeln(‘             j值从i-1开始向前扫描,边扫描边将数据后移,寻找到位置,插入当前值.‘);
       writeln;
       writeln(‘算法时间复杂度为O(n^2)‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=3 then
      begin
       writeln(‘var a:array[0..1000] of longint;‘);
       writeln(‘    n,i,j:longint;‘);
       writeln(‘begin‘);
       writeln(‘ readln(n);‘);
       writeln(‘ for i:= 1 to n do read(a[i]);‘);
       writeln(‘ for i:=2 to n do‘);
       writeln(‘  begin‘);
       writeln(‘   a[0]:=a[i];j:=i-1;‘);
       writeln(‘   while (a[0]<a[j]) and (j>0) do‘);
       writeln(‘    begin a[j+1]:=a[j];j:=j-1 end;‘);
       writeln(‘   a[j+1]:=a[0];‘);
       writeln(‘  end;‘);
       writeln(‘ for i:= 1 to n do write(a[i]:6);‘);
       writeln(‘ end.‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=1 then
      begin
       writeln(‘请输入演示数据的个数(系统将随机产生数据),建议不超过15:‘);
       readln(n);
       for i:=1 to n do
         a[i]:=random(1000);
       write(‘未排序前:‘);
       for i:=1 to n do
         write(a[i],‘ ‘);
       writeln;
       insertionsort(a);
       clrscr;
       goto 2;
      end;
   end;
 if choose1=4 then
   begin
     clrscr;
     if choose2=2 then
      begin
       writeln(‘(1)首先从待排序区间(初始时为[1..n])中选取一个元素作为基准元素;‘);
       writeln(‘   (方便起见,一般是选取区间内的第一个元素)‘);
       writeln;
       writeln(‘(2)然后从两端向中间依次进行比较和交换，‘);
       writeln(‘   把位于基准元素之前且比基准元素大的交换到后面;‘);
       writeln(‘   把位于基准元素之后且比基准元素小的交换到前面‘);
       writeln;
       writeln(‘(3)直至基准元素位于前后两部分的交界处‘);
       writeln(‘   这样前面部分的所有元素都小于等于基准元素‘);
       writeln(‘   后面部分的所有元素均大于等于基准元素‘);
       writeln(‘   基准元素的所在位置就是排序后的最终位置‘);
       writeln;
       writeln(‘(4)然后再对基准元素的前后两个区间分别进行快速排序‘);
       writeln(‘   直至每个区间为空或只包含一个元素，整个快速排序结束‘);
       writeln;
       writeln(‘最理想时间复杂度:O(nlogn);‘);
       writeln(‘最差时间复杂度:O(n^2)‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=3 then
      begin
       writeln(‘var n,i:longint;‘);
       writeln(‘    d:array[1..10000]of longint;‘);
       writeln(‘procedure qsort(head,tail:longint);‘);
       writeln(‘var x,i,j:longint;‘);
       writeln(‘begin‘);
       writeln(‘   x:=d[head];  i:=head;  j:=tail;‘);
       writeln(‘   while i<j do‘);
       writeln(‘   begin‘);
       writeln(‘      while(i<j)and(d[j]>=x)do j:=j-1;‘);
       writeln(‘      d[i]:=d[j];‘);
       writeln(‘      while(i<j)and(d[i]<=x)do i:=i+1;‘);
       writeln(‘      d[j]:=d[i];‘);
       writeln(‘   end;‘);
       writeln(‘   d[i]:=x;‘);
       writeln(‘   if head<j-1 then qsort(head,j-1);‘);
       writeln(‘   if i+1<tail then qsort(i+1,tail);‘);
       writeln(‘end;‘);
       writeln(‘begin‘);
       writeln(‘    readln(n);‘);
       writeln(‘    for i:=1 to n do read(d[i]);‘);
       writeln(‘    qsort(1,n);‘);
       writeln(‘    for i:=1 to n do writeln(d[i]);‘);
       writeln(‘end.‘);
       readln;
       clrscr;
       goto 2;
      end;
     if choose2=1 then
      begin
       cou:=0;
       write(‘请输入演示数据的个数(系统将随机产生数据),建议不超过15:‘);
       writeln;
       readln(n);
       for i:=1 to n do
         a[i]:=random(1000);
       write(‘未排序前:‘);
       for i:=1 to n do
         write(a[i],‘ ‘);
       writeln;
       qsort(a,1,n);
       writeln(‘排序完毕!‘);
       readln;
       clrscr;
       goto 2;
      end;
   end;
  if choose2=0 then goto 1;
end.