高精度/sgu112 a^b - b^a

题意

　　给出一个a一个b，求a^b - b^a

分析

　　高精度不解释

　　需要写三个高精度：

　　　　mult-计算乘法

　　　　compare-比较两个数的大小

　　　　minus-计算减法

Accepted Code

 1 {
 2     PROBLEM:SGU112
 3     AUTHER:Rinyo
 4     MEMO:高精度 模拟
 5 }
 6 Program sgu112;
 7 Type
 8   Rec = REcord
 9     len:Longint;
10     a:Array[0..1130]Of Longint;
11   End;
12 Var
13   a,b,aa,bb,i:Longint;
14   flag:Boolean;
15   aaa,bbb:REc;
16 Procedure mult(var a:Rec;k:Longint);
17 Var
18   i:Longint;
19 Begin
20   For i:=1 To a.len Do a.a[i]:=a.a[i]*k;
21   For i:=1 To a.len-1 Do Begin
22     Inc(a.a[i+1],a.a[i] Div 10);
23     a.a[i]:=a.a[i] Mod 10;
24   End;
25   i:=a.len;
26   While a.a[i]>9 Do Begin
27     Inc(a.a[i+1],a.a[i] Div 10);
28     a.a[i]:=a.a[i] Mod 10;
29     Inc(i);
30   End;
31   a.len:=i;
32 End;
33 Function compare(a,b:REc):Boolean;
34 Var
35   i:Longint;
36 Begin
37   If a.len<>b.len Then Begin
38     compare:=a.len>b.len;
39     Exit;
40   End Else
41   Begin
42     compare:=true;
43     For i:=a.len Downto 1 Do
44       If a.a[i]<>b.a[i] Then Begin
45         compare:=a.a[i]>b.a[i];
46         Exit;
47       End;
48   End;
49 End;
50 
51 Function minus(a,b:Rec):Rec;
52 Var
53   i:Longint;
54 Begin
55   For i:=1 To a.len Do Begin
56     a.a[i]:=a.a[i]-b.a[i];
57     If a.a[i]<0 Then Begin
58       Inc(a.a[i],10);
59       Dec(a.a[i+1]);
60     End;
61   End;
62   i:=a.len;
63   While (a.a[i]=0) And (i>1) Do Dec(i);
64   a.len:=i;
65   minus:=a;
66 End;
67 
68 Begin
69   ReadLn(a,b);
70   aa:=a;bb:=b;
71   aaa.len:=0;bbb.len:=0;
72   WHile aa>0 Do Begin
73     Inc(aaa.len);
74     aaa.a[aaa.len]:=aa Mod 10;
75     aa:=aa Div 10;
76   End;
77   While bb>0 Do Begin
78     Inc(bbb.len);
79     bbb.a[bbb.len]:=bb Mod 10;
80     bb:=bb Div 10;
81   End;
82   For i:=2 To b Do mult(aaa,a);
83   For i:=2 To a Do mult(bbb,b);
84   flag:=compare(aaa,bbb);
85   If flag Then aaa:=minus(aaa,bbb)
86           Else Begin
87             Write('-');
88             aaa:=minus(bbb,aaa);
89           End;
90   For i:=aaa.len Downto 1 Do Write(aaa.a[i]);
91   WriteLn;
92 End.

 

posted @ 2012-12-16 15:27  Rinyo  阅读(275)  评论(0)  编辑  收藏  举报