POJ 1007(求逆序对数）

求逆序对数，2关键字排序

Program P1007;var   n,m,i,j,k,l,p:longint;   a:array[1..200] of string;   s:string;   b,num:array[1..200] of longint;function h(s:string):longint;var   i,j,a,c,g,t:longint;begin   a:=0;   c:=0;   g:=0;   t:=0;   h:=0;   for i:=length(s) downto 1 do   begin      if s[i]='A' then inc(a);      if s[i]='C' then      begin         inc(c);         inc(h,a);      end;      if s[i]='G' then      begin         inc(g);         inc(h,a+c);      end;      if s[i]='T' then      begin         inc(t);         inc(h,a+c+g);      end;   end;end;procedure qsort(l,r:longint);var   i,j,m,p:longint;   s2:string;begin   i:=l;   j:=r;   m:=b[(l+r) div 2];   repeat      while b[i]<m do inc(i);      while b[j]>m do dec(j);      if i<=j then      begin         p:=b[i];         b[i]:=b[j];         b[j]:=p;         p:=num[i];         num[i]:=num[j];         num[j]:=p;{         s2:=a[i];         a[i]:=a[j];         a[j]:=s2;}        inc(i);         dec(j);      end;   until i>j;   if l<j then qsort(l,j);   if i<r then qsort(i,r);end;begin   readln(n,m);   for i:=1 to m do   begin      readln(a[i]);      b[i]:=h(a[i]);      num[i]:=i;   end;   qsort(1,m);   i:=1;   while (i<m) do   begin      if b[i]<b[i+1] then inc(i)      else      begin         for j:=i+1 to m do if b[j]<>b[i] then break;         if (b[i]<>b[m]) then dec(J);         for k:=i to j-1 do            for l:=k+1 to j do               if num[k]>num[l] then               begin                  p:=num[k];                  num[k]:=num[l];                  num[l]:=p; {                 s:=a[k];                  a[k]:=a[l];                  a[l]:=s;  }             end;         i:=j+1;      end;   end;   for i:=1 to m do writeln(a[num[i]]);end.