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高精度，用一个线性表保存一个大整数，具体说，将大整数写成p进制数，线性表的每一项存p进制其中一位。 参考下面代码 #include <iostream>; H9 |7 |" L! l+ Y
#include <memory>( f `4 c% w! m' n* v5 p
# include <string>
# L0 m+ [& ?) |1 X' |. x, d/ F4 busing namespace std; typedef long long hugeint; const int Base = 1000000000;8 o- |9 i' S4 w) T4 Y
const int Capacity = 200; struct xnum
( V3 a: G; j5 @/ l{
, h( U s. ^8 |4 D- }# `+ s3 n int Len;9 z! g* X& @9 i9 o$ E q+ ?
int Data[Capacity];
5 W' ]$ o( _7 i/ R xnum() : Len(0) {}! {0 h1 D5 R, v
xnum(const xnum& V) : Len(V.Len) { memcpy(Data, V.Data, Len * sizeof *Data); }4 ~% @5 g6 R2 P% q
xnum(int V) : Len(0) { for (; V > 0; V /= Base) Data[Len++] = V % Base; } O' Q: r% W# ]6 Z' c# B- H
xnum& operator=(const xnum& V) { Len = V.Len; memcpy(Data, V.Data, Len * sizeof *Data); return *this; }
6 M: x6 S3 h( K9 T& I int& operator[](int Index) { return Data[Index]; }
( A& ?4 I5 a/ f5 X: { int operator[](int Index) const { return Data[Index]; }
% o: z+ c; Q7 Q( S* G}; $ A( |% d9 R, N3 d- p5 O3 b
int compare(const xnum& A, const xnum& B)
* G; a: Q* H. _/ ?; ]% W{
4 ~( r' n4 q$ H int I;
, y8 b/ [ F5 z( F+ _% \$ J B if (A.Len != B.Len) return A.Len > B.Len ? 1 : -1;, o8 t, M4 a3 F* s
for (I = A.Len - 1; I >= 0 && A[I] == B[I]; I--);; v! j H& C7 `( h1 |, I) B( Z
if (I < 0) return 0;
6 v% U6 d3 ?' Q9 @& J5 z! Q# C" h return A[I] > B[I] ? 1 : -1;
7 ^9 j8 o# p* r# Q; }8 K F} xnum operator+(const xnum& A, const xnum& B), }8 \- r. x* ^' v# J' J
{3 f" y% h$ k* I0 x5 a
xnum R;$ |% h7 D* j }9 U* x* [
int I;
. q' v. Z7 A5 } int Carry = 0;& Q$ i% q* M! T3 |( t
for (I = 0; I < A.Len || I < B.Len || Carry > 0; I++)
- E! A; [& L4 ~# F+ N {
9 D6 B* t. t( B, U- Q9 f if (I < A.Len) Carry += A[I];
; J. `7 p- I1 a; y) s! u if (I < B.Len) Carry += B[I];
4 |! Z7 u- p! e W8 }+ V R[I] = Carry % Base;
# g9 b7 d7 r* F' B5 P& t Carry /= Base;1 @! A4 `. R1 w# H
}
. |6 b/ r- A! {3 }$ B$ k0 R* f R.Len = I;" H* d! x) g$ E) s$ e, B
return R;
5 B% F5 |, y* i: L/ a0 x} xnum operator-(const xnum& A, const xnum& B)2 C$ _) @8 J6 P0 W/ \" C" |
{5 `: c3 C& n( `0 W% g0 L
xnum R;0 H8 |. R$ v& y) e5 |! |
int Carry = 0;
" t9 u, ^+ W# e" k9 ? R.Len = A.Len;! m3 i# g/ e/ L, H8 j
int I;
2 S' f% E( r4 S, F' Q. D6 s$ e2 } for (I = 0; I < R.Len; I++)4 L7 G- B j4 q7 K+ P8 g
{
8 e% E9 j* n' T R[I] = A[I] - Carry;
1 B5 C4 x3 E, |' j if (I < B.Len) R[I] -= B[I];) G. q6 \* P% Y8 q
if (R[I] < 0) Carry = 1, R[I] += Base;# _+ h. ~$ R/ a8 y
else Carry = 0;
" a* G' b' i7 O% O }
/ @3 P+ P2 D( C; { while (R.Len > 0 && R[R.Len - 1] == 0) R.Len--;6 P6 k# _, C% F! y* V7 a& w
return R;
+ a3 D6 h' @7 P} xnum operator*(const xnum& A, const int B)
( n* X6 C0 _+ d4 ]{
) u' u& f# p5 A. A" [6 l" a- f int I;1 K2 b! b' B' c
if (B == 0) return 0;
; b# A# {$ H5 d, l3 k xnum R;2 v" E$ b6 U+ j+ |$ y( ~- L; x1 K8 B
hugeint Carry = 0;) B. O7 h* e% U( ^! M
for (I = 0; I < A.Len || Carry > 0; I++)
: ^; c6 M3 y5 y3 t# J+ ]1 ] {3 `0 B# R3 o! p5 ~" h- _
if (I < A.Len) Carry += hugeint(A[I]) * B;! M! p( m( |, y0 x' D; j1 b Y
R[I] = Carry % Base;, o; s7 n/ z* [% D; ^5 f
Carry /= Base;) q# t% J2 P7 h
}
9 d1 Y- k. K; S! ~; `& ^ R.Len = I;: ~2 D( H7 C2 U" B- Q! q p
return R;
) G# H* |* X0 X P) T} xnum operator*(const xnum& A, const xnum& B)
d8 ]2 {' @! y* H% T! [{
4 g2 o5 p# x. \+ O/ | int I;
; X/ S: [" y" p' J5 r+ g if (B.Len == 0) return 0;
6 A* _& ]4 e# [* J. h z xnum R;* M6 {3 q3 X7 o
for (I = 0; I < A.Len; I++)
+ ^9 w8 [% N; F1 x% z) w+ T {" S H* w3 N7 z; j, J
hugeint Carry = 0;
% ?* O5 P$ D4 A for (int J = 0; J < B.Len || Carry > 0; J++)- p9 Y0 J% _4 V7 k
{5 R# Y \" ?8 T/ x; H
if (J < B.Len) Carry += hugeint(A[I]) * B[J];
; T. v1 ?( }* C8 Y3 | z if (I + J < R.Len) Carry += R[I + J];2 b2 e4 B7 {6 r9 B8 `, t2 b9 z$ Z
if (I + J >= R.Len) R[R.Len++] = Carry % Base;% M' q" l7 Q& N) Q4 ^
else R[I + J] = Carry % Base;
, o8 z2 _- W, p+ c( B% P, H Carry /= Base;
! U0 E, Z0 y2 t* Y4 o } 3 W( R- K' @- e( v
}. c1 ` \! H2 Z5 g# ]9 w1 _( T
return R;
( ]% B) ~( I! o} xnum operator/(const xnum& A, const int B)
+ ?8 I" d4 e' P) i! L{; n2 R. {% ] @# D- J9 v
xnum R;) A9 A: p2 z, D3 V( l" Z
int I;+ B" M; f9 J$ } l
hugeint C = 0;7 k4 X0 N+ Q- \; P2 J+ \+ o
for (I = A.Len - 1; I >= 0; I--)
* L% f* _- T# F {
( s3 K3 f! a- y T C = C * Base + A[I];
) r5 K5 w# T$ D" O, C# ? R[I] = C / B;7 g* v$ G ~- D# D3 a9 o
C %= B;% B* G/ Z% p% z6 i, }3 c3 T, M
}
l8 U( [* K5 q+ h6 _; ]8 B5 ]( H R.Len = A.Len;
: {. A- D) i4 Y" ~7 L0 D while (R.Len > 0 && R[R.Len - 1] == 0) R.Len--;
6 O) ]3 `, `" } d return R;
' ?, I- \* _5 m* _5 O} xnum operator/(const xnum& A, const xnum& B), {: [6 s: G$ l/ l! B b
{
8 k( o& D0 M+ P3 @; ^2 z int I;# F* x1 @% f$ m7 r8 a c
xnum R, Carry = 0;1 i4 `, L h+ n4 c9 C4 P9 |( [
int Left, Right, Mid;, z3 G/ ^9 M* `4 i
for (I = A.Len - 1; I >= 0; I--)
9 m3 O" b( r- e& E# e4 I# M {
" F& X0 m4 r2 ], {1 o- N: D Carry = Carry * Base + A[I];; A, f* Q2 c/ P7 H
Left = 0;5 d6 k4 B n, Q0 O% z$ z5 A5 c
Right = Base - 1;
+ G7 ^5 {5 _ w. M @& G( W while (Left < Right)4 f+ o0 t. o, X0 G/ n1 w% n
{
j1 H4 a& N& K6 ] Mid = (Left + Right + 1) / 2;7 g- j1 I* l) U% y
if (compare(B * Mid, Carry) <= 0) Left = Mid;- h6 e ?0 S2 R3 T- n* `; y
else Right = Mid - 1;3 `, t; q5 C8 G& T2 m
}! \9 j6 U" u0 C6 L3 v+ }% F. N% U
R[I] = Left;* }! Q& W" t+ m' N$ F4 J
Carry = Carry - B * Left; y" o8 \8 A6 _' m: D7 L
}0 }& d7 V) A0 G6 n8 `9 @$ t
R.Len = A.Len;
3 L1 \) j* t, i' O% ] while (R.Len > 0 && R[R.Len - 1] == 0) R.Len--;; o( D# i$ c" l5 x9 ^. v+ ^& a5 O
return R;' P) ?" ?+ u0 o q, y: ^2 d
}
& E& {2 Q( s( e% {; E, b+ Wxnum operator%(const xnum& A, const xnum& B)
) K; ~' m( c [. v{
+ u! Y& A% |" v. v int I;
9 R" N+ i% s; x, T) z xnum R, Carry = 0;8 _- H/ d; }/ P5 f' q- U1 {
int Left, Right, Mid; E5 f3 v2 c8 g; Y+ b
for (I = A.Len - 1; I >= 0; I--)
4 F4 T3 x S. L n2 } {
" s9 O3 x% }, y# m5 W Carry = Carry * Base + A[I];
9 U" ^) ~+ i9 q* t. s$ @. k Left = 0;
; D3 v. {8 F0 H' h Right = Base - 1;
* ?0 e5 r. {8 v0 ^; g$ E while (Left < Right)
" ?$ ]3 W# e4 |* k3 ^2 i: k% m {
9 ?( F, H2 i0 s1 d+ B: l# G# S+ _$ D Mid = (Left + Right + 1) / 2;. s* P& b/ O! b! d# w3 v S
if (compare(B * Mid, Carry) <= 0) Left = Mid;
/ a1 u) _! o F$ |" } else Right = Mid - 1;
/ O8 A* _ S( S1 u }
$ ?0 h- `/ a# P( g8 i6 W R[I] = Left;
! g3 A9 O/ g8 H7 [2 X/ N Carry = Carry - B * Left;" a, s8 z& y: V
}$ T, {, ~1 u. t' l) R/ \. T H
R.Len = A.Len;# \2 h" P$ A6 g- b/ o; p& E2 w/ }
while (R.Len > 0 && R[R.Len - 1] == 0) R.Len--;1 Q3 ]) C8 h1 f7 f
return Carry;
% d+ ^; I* @+ G% Z% u4 G/ n} istream& operator>>(istream& In, xnum& V)( s9 o& @8 {" S
{
0 J! W$ f8 V+ r0 m: A char Ch;
% c/ V" h5 G: d, |- N# C for (V = 0; In >> Ch;)
7 ^0 W# D4 }' n" [# w {
; c' E& P) z, |- p' B' b V = V * 10 + (Ch - '0');
- ^" u; N8 w) C7 ?! w8 u# D% } if (cin.peek() <= ' ') break;
) _$ o" |3 Z% l6 P }! }5 d% x! ]9 W+ Y9 F: [% }1 {% Z
return In;
# u V% _1 s$ x" P} ostream& operator<<(ostream& Out, const xnum& V) i# \& L2 u& l. w
{1 x- a* Y( I# a" Z) f* j
int I;
: j0 e' o! y4 V Out << (V.Len == 0 ? 0 : V[V.Len - 1]);
+ y' {. q& c5 F3 w& Y( `0 ` for (I = V.Len - 2; I >= 0; I--) for (int J = Base / 10; J > 0; J /= 10) Out << V[I] / J % 10;3 D. _2 u" o8 \) p: o- A! K
return Out;
' R3 F) C2 Q% E1 A+ ]. a} R P, G/ A. g9 R' B& _
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发表于 2005-2-1 16:07
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