ZYM/BH-int2048-2023
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feat: ready to optimize performance

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This commit is contained in:
ZhuangYumin
2023-10-31 07:34:02 +08:00
parent 4f38a2b8f9
commit 5f8e0e8622
5 changed files with 73 additions and 33 deletions
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58
src/int2048.cpp
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@ -25,6 +25,7 @@
#include <cstdio>
#include <cstring>
#include <iostream>
#include <utility>
static_assert(sizeof(int) == 4, "sizeof(int) != 4");
@ -135,11 +136,16 @@ void int2048::read(const std::string &input_value) {
// 输出储存的大整数，无需换行
void int2048::print() {
// 实现输出逻辑
if (flag == -1) putchar('-');
char *buf = new char[num_length + 5];
char *p = buf;
if (flag == -1) *p++ = '-';
const static int kPow10[9] = {1, 10, 100, 1000, 10000,
100000, 1000000, 10000000, 100000000};
for (int i = num_length - 1; i >= 0; i--)
putchar('0' + val[i / kNum] / kPow10[i % kNum] % 10);
*p++ = char('0' + val[i / int2048::kNum] / kPow10[i % int2048::kNum] % 10);
*p++ = 0;
std::cout << buf;
delete[] buf;
}
void int2048::ClaimMem(size_t number_length) {
@ -524,9 +530,32 @@ inline void UnsignedDivide(int2048 &A, const int2048 *pB) {
x.num_length--;
if (x.num_length == 0) throw "UnsignedMultiply: num_length==0";
}
/*check the highest number of B*/
if (pB->val[(pB->num_length - 1) / int2048::kNum] /
kPow10[(pB->num_length - 1) % int2048::kNum] ==
1) {
/* x=5*x */
int2048 tmp(x);
tmp.add(tmp);
tmp.add(tmp);
x.add(tmp);
} else if (pB->val[(pB->num_length - 1) / int2048::kNum] /
kPow10[(pB->num_length - 1) % int2048::kNum] <
3) {
/* x=3*x */
int2048 tmp(x);
tmp.add(tmp);
x.add(tmp);
} else if (pB->val[(pB->num_length - 1) / int2048::kNum] /
kPow10[(pB->num_length - 1) % int2048::kNum] <
5) {
/* x=2*x */
x.add(x);
}
int2048 x_pre(x);
int2048 kOne(1);
UnsignedMinus(x_pre, &kOne);
int cnt = 0;
while (true) {
/**
* x_{n+1}=2*x_n-x_n*x_n*B/(10^L1))
@ -542,6 +571,7 @@ inline void UnsignedDivide(int2048 &A, const int2048 *pB) {
if (UnsignedCmp(x_next, x_pre) == 0) break;
x_pre = std::move(x);
x = std::move(x_next);
cnt++;
}
/*ret=A*x/10^(L1)*/
UnsignedMultiply(x, &A);
@ -559,7 +589,9 @@ inline void UnsignedDivide(int2048 &A, const int2048 *pB) {
while (UnsignedCmp(remain, *pB) >= 0) {
UnsignedMinus(remain, pB);
UnsignedAdd(x, &kOne);
// cnt++;
}
std::cerr << cnt << std::endl;
A = std::move(x);
}
int2048 &int2048::Divide(const int2048 &B) {
@ -602,15 +634,18 @@ int2048 operator/(int2048 A, const int2048 &B) {
int2048 &int2048::operator%=(const int2048 &B) {
// 实现复合取模逻辑
int2048 C = (*this) / B;
*this = *this - C * B;
int2048 C(*this);
C.Divide(B);
this->minus(C.Multiply(B));
return *this;
}
int2048 operator%(int2048 A, const int2048 &B) {
// 实现取模逻辑
int2048 C = A / B;
return A - C * B;
int2048 C(A);
C.Divide(B);
A.minus(C.Multiply(B));
return std::move(A);
}
std::istream &operator>>(std::istream &stream, int2048 &V) {
@ -623,12 +658,17 @@ std::istream &operator>>(std::istream &stream, int2048 &V) {
std::ostream &operator<<(std::ostream &stream, const int2048 &v) {
// 实现输出运算符逻辑
if (v.flag == -1) stream << '-';
char *buf = new char[v.num_length + 5];
char *p = buf;
if (v.flag == -1) *p++ = '-';
const static int kPow10[9] = {1, 10, 100, 1000, 10000,
100000, 1000000, 10000000, 100000000};
for (int i = v.num_length - 1; i >= 0; i--)
stream << char('0' +
v.val[i / int2048::kNum] / kPow10[i % int2048::kNum] % 10);
*p++ =
char('0' + v.val[i / int2048::kNum] / kPow10[i % int2048::kNum] % 10);
*p++ = 0;
stream << buf;
delete[] buf;
return stream;
}