PLSQL实现排序(冒泡、选择、快速)

转载 http://duqiangatom.blog.163.com/blog/static/11502518201051181157657/
1、起泡排序法（平均时间复杂）

分析：若是正序，则j=n-1趟排序，每次进行n-j次比较，且不移动记录；

反之，要进行(n-1 + 1 ) * (n-1) /2次；总的时间复杂度为O(n平方)

create or replace function f_bible_sort(p_numbers in varchar2) return varchar2 is
Result varchar2(4000);

type t_table is table of char index by pls_integer;
v_tab t_table;
v_tmp char;
begin
for i in 1 .. nvl(length(p_numbers), 0) loop
v_tab(i) := substr(p_numbers, i, 1);
end loop;

for p in 1 .. nvl(length(p_numbers), 0) - 1 loop
for q in reverse p .. nvl(length(p_numbers), 0)-1 loop ---一定要从冒泡轨迹的起点开始比较。
if v_tab(q) <= v_tab(q+1) then

v_tmp := v_tab(q);
v_tab(q) := v_tab(q+1);
v_tab(q+1) := v_tmp;
end if;
end loop;
end loop;

for i in 1 .. nvl(length(p_numbers), 0) loop
Result := Result || v_tab(i);
end loop;

return(Result);
end f_bible_sort;

2、选择排序法

create or replace function f_choice_sort(p_numbers in varchar2) return varchar2 is
Result varchar2(4000);

type t_table is table of char index by pls_integer;
v_tab t_table;
v_tmp char;
begin
for i in 1 .. nvl(length(p_numbers), 0) loop
v_tab(i) := substr(p_numbers, i, 1);
end loop;

for p in 1 .. nvl(length(p_numbers), 0) - 1 loop
for q in p + 1 .. nvl(length(p_numbers), 0) loop
if v_tab(p) <= v_tab(q) then

v_tmp := v_tab(p);
v_tab(p) := v_tab(q);
v_tab(q) := v_tmp;
end if;
end loop;
end loop;

for i in 1 .. nvl(length(p_numbers), 0) loop
Result := Result || v_tab(i);
end loop;

return(Result);
end;
3、快速排序

1、借助包体创建索引数组类型（作为排序传入参数使用）

create or replace package t_array_pkg as
type t_array is table of number index by binary_integer;
end t_array_pkg;

2、排序存储过程

CREATE OR REPLACE procedure p_quick_sort(v_arr IN out t_array_pkg.t_array,
low in INT,
high in INT) IS

v_key_position INT;
v_low INT := low;
v_high INT := high;

--begin 以第一个元素为键值，差分为2组，并返回key值所在数组下标
procedure p_partitions(v_arr IN out t_array_pkg.t_array, low in INT, high in INT,position out int) IS
v_tmp number;
v_key int;
v_low int :=low;
v_high int :=high;
/* RESULT VARCHAR2(2000);*/
BEGIN

v_key := v_arr(v_low);

WHILE (v_low < v_high) LOOP

WHILE (v_low < v_high AND v_arr(v_high) >= v_key) LOOP
v_high := v_high - 1;
END LOOP;
v_tmp := v_arr(v_low);
v_arr(v_low) := v_arr(v_high);
v_arr(v_high) := v_tmp;
WHILE (v_low < v_high AND v_arr(v_low) <= v_key) LOOP
v_low := v_low + 1;
END LOOP;
v_tmp := v_arr(v_high);
v_arr(v_high) := v_arr(v_low);
v_arr(v_low) := v_tmp;

END LOOP;

v_arr(v_low) := v_key;

/*for i in 1 .. v_arr.count loop
Result := Result || v_arr(i)||',';
end loop;
dbms_output.put_line(Result);*/
position :=v_low;
END;
--end

BEGIN

if (low < high) then
p_partitions(v_arr, low, high, v_key_position);
p_quick_sort(v_arr, v_low, v_key_position - 1);
p_quick_sort(v_arr, v_key_position + 1, v_high);
end if;

/* for i in 1 .. v_arr.count loop
Result := Result || v_arr(i)||',';
end loop;
dbms_output.put_line(Result);*/
END;
3、排序调用

declare
v_arr t_array_pkg.t_array;
v_result varchar2(2000);
begin
---初始化要排序的数组
v_arr(1) := 33;
v_arr(2) := 11;
v_arr(3) := 44;
v_arr(4) := 4;
v_arr(5) := 3;
v_arr(6) := 2;

--快速排序
p_quick_sort(v_arr => v_arr, low => :low, high => :high);

--打印快速排序结果
for i in 1 .. v_arr.count loop
v_result := v_result || v_arr(i)||',';
end loop;
dbms_output.put_line(substr(v_result,1,length(v_result)-1));
end;

注意：也可以借助创建类型来实现 declare
v_arr t_array;
v_result varchar2(2000);
begin
---初始化要排序的数组
v_arr :=t_array();
v_arr.extend(6);
v_arr(1) := 33;
v_arr(2) := 11;
v_arr(3) := 44;
v_arr(4) := 4;
v_arr(5) := 3;
v_arr(6) := 2;

--快速排序
p_quick_sort(v_arr => v_arr, low => :low, high => :high);

--打印快速排序结果
for i in 1 .. v_arr.count loop
v_result := v_result || v_arr(i)||',';
end loop;
dbms_output.put_line(substr(v_result,1,length(v_result)-1));
end;

==================================================================

1、create type t_array is table of number ; ---创建数组类型

2、将p_quick_sort中的所有数组参数类型t_array_pkg.t_array 换为t_array ；

3、调用排序

declare
v_arr t_array;
v_result varchar2(2000);
begin
---初始化要排序的数组
v_arr :=t_array();
v_arr.extend(6);
v_arr(1) := 33;
v_arr(2) := 11;
v_arr(3) := 44;
v_arr(4) := 4;
v_arr(5) := 3;
v_arr(6) := 2;

--快速排序
p_quick_sort(v_arr => v_arr, low => :low, high => :high);

--打印快速排序结果
for i in 1 .. v_arr.count loop
v_result := v_result || v_arr(i)||',';
end loop;
dbms_output.put_line(substr(v_result,1,length(v_result)-1));
end;