排序算法--插入、快排、选择、冒泡、堆排序、归并

1.插入排序：

procedure in_sort(var a: array of Integer; k, m: Integer);
var
  p: Integer;
begin
  p := 0;
  while p = 0 do
  begin
    if k >= a[m] then
    begin
      a[m + 1] := k;
      p := 1;
    end
    else
    begin
      a[m + 1] := a[m];
      Dec(m);
      if m = -1 then
      begin
        a[m + 1] := k;
        p := 1;
      end;
    end;
  end;
end;

2.快速排序：

procedure q_sort(var a: array of Integer; l, r: Integer);
var
  i, j, mid, t: Integer;
begin
  i := l;
  j := r;
  mid := a[(l + r) div 2];
  while i <= j do
  begin
    while (a[i] < mid) do
      Inc(i);
    while (a[j] > mid) do
      Dec(j);
    if i <= j then
    begin
      t := a[i];
      a[i] := a[j];
      a[j] := t;
      Inc(i);
      Dec(j);
    end;
  end;
  if l < j then
    q_sort(a, l, j);
  if i < r then
    q_sort(a, i, r);
end;

3.选择排序：

procedure sel_sort(var a: array of Integer; l, r: Integer);
var
  i, j, k, t: Integer;
begin
  for i := l to r do
  begin
    k := i;
    for j := i + 1 to r do
    begin
      if a[j] < a[k] then
        k := j;
    end;
    if k <> i then
    begin
      t := a[k];
      a[k] := a[i];
      a[i] := t;
    end;
  end;
end;

4.冒泡排序：

procedure b_sort(var a: array of Integer; l, r: Integer);
//l,r表示上下标
var
  i, j, t: Integer;
begin
  for i := l to r do
    for j := l to i - 1 do
    begin
      if a[j] > a[i] then
      begin
        t := a[i];
        a[i] := a[j];
        a[j] := t;
      end;
    end;
end;

5.堆排序：

procedure heap_adjust(var a: array of Integer; i, m: Integer);
var
  k, t: Integer;
begin
  t := a[i];
  k := i * 2;
  while k <= m do
  begin
    if (a[k] < a[k + 1]) and (k < m) then
      Inc(k);
    if (t < a[k]) then
    begin
      a[i] := a[k];
      i := k;
      k := 2 * i; //调整，并为t在下面节点找位置
      //k向下探索
    end
    else
      k := m + 1;
  end;
  a[i] := t;
end;
procedure he_sort(var a: array of Integer; l, r: Integer);
var
  j, t: Integer;
begin
  for j := r div 2 to l do
    heap_adjust(a, j, r);
  //调整堆，初始化
  for j := r downto l do
  begin
    t := a[0];
    a[0] := a[j];
    a[j] := t;
    heap_adjust(a, l, j - 1);
  end;
end;

6.归并排序：

procedure merge(var a: array of Integer; l, q, r: Integer);
{将已排序好的子序列a[l..p]与a[q+1..r]合并为有序的tmp[l..r]}
var
  i, j, t: Integer;
  tmp: array[0..20] of Integer;
begin
  i := l;
  j := q + 1;
  t := l;
  while t <= r do
  begin
    if ((i <= q) and (a[i] <= a[j])) or (j > r) then
    begin
      tmp[t] := a[i];
      Inc(i);
    end
    else
    begin
      tmp[t] := a[j];
      Inc(j);
    end;
    Inc(t);
  end;
  for t := l to r do
    a[t] := tmp[t];
end;
procedure me_sort(var a: array of Integer; l, r: Integer);
var
  q: Integer;
begin
  if l <> r then
  begin
    q := (l + r) div 2;
    me_sort(a, l, q);
    me_sort(a, q + 1, r);
    merge(a, l, q, r);
  end;
end;