BigNum BigNum::operator /(const BigNum& operand) const {
std::vector<uint8_t> quotient, current;
bool started = false;
for (ssize_t i = data.size() - 1; i >= 0; i--) {
current.push_back(data[i]);
BigNum bcurrent(current);
uint8_t q = bcurrent.smallDivide(operand);
current = (bcurrent - ((operand) * BigNum(q))).toVector();
if (started or q != 0) {
started = true;
quotient.push_back(q);
}
}
return BigNum(quotient, negative xor operand.negative);
}
void DhHandshake::set_config(int32 g_int, Slice prime_str) {
has_config_ = true;
prime_ = BigNum::from_binary(prime_str);
prime_str_ = prime_str.str();
b_ = BigNum();
g_b_ = BigNum();
BigNum::random(b_, 2048, -1, 0);
// g^b
g_int_ = g_int;
g_.set_value(g_int_);
BigNum::mod_exp(g_b_, g_, b_, prime_, ctx_);
}
BigNum BigNum::operator +(const BigNum& operand) const {
if (negative)
return -((-*this) + -operand);
if (operand.negative) { //compare
BigNum abs(operand.abs());
if (operator==(abs))
return BigNum(0);
if (operator<(abs))
return -(abs - *this);
//do subtract here
//we are sure here: *this > operand (strictly)
vector<uint8_t> ret(data);
int carry = 0;
for (int i = 0; i < data.size(); i++) {
if (i < operand.data.size())
//if digit exists in b
carry += operand.data[i];
int tmp = (int) ret[i] - carry;
if (tmp < 0) {
carry = 1;
ret[i] = tmp + (1 << 8);
} else {
ret[i] = tmp;
carry = 0;
}
}
//because *this > operand. carry must be 0 here
//this refinement is redudant but just because of the sake of logic
while (not ret.empty() and *ret.rbegin() == 0)
ret.pop_back();
BigNum big(0);
big.data = ret;
return big;
}
//do plus here
vector<uint8_t> ret(data);
int carry = 0;
for (int i = 0; i < data.size(); i++) {
if (i < operand.data.size())
//if digit exists in b
carry += operand.data[i];
int tmp = (int) ret[i] + carry;
carry = tmp >> 8;
ret[i] = tmp bitand ((1 << 8) - 1);
}
while (carry > 0) {
ret.push_back(carry & ((1 << 8) - 1));
carry >>= 8;
}
while (not ret.empty() and *ret.rbegin() == 0)
ret.pop_back();
BigNum r(0);
r.data = ret;
return r;
}
int main()
{
int a[10]={1,2,3,4,5,6,7,8,9,10};
//创建链表
LinkInfo *L=CreateInfoFromArray(a,10);
//1-单链表反转
ReverseList(L);
ReverseList(L);
//2-倒数第K个的验证
node* last[11];
for(int i=0;i<11;i++)
last[i]=lastK(*L,i+1);
//3-中间元素
node* mid=FinMid(*L);
//4-删除无头结点
//DelNoHead(L->head->next);
//5-有序链表合并
int a1[5]={5,5,4,3,1};
int b1[3]={7,4,2};
LinkInfo *p=CreateInfoFromArray(a1,0);//测试案例: 1-p,q 递增 2-p,q递减 3-p为空 4-q为空 5-p,q均为空
LinkInfo *q=CreateInfoFromArray(b1,3);
MergeList(p,q);
//6-判断链表是否有环（并返回环的起点node*）
LinkInfo *circle=CreateInfoFromArray(a,6);//测试：有环、无环、空链表
node *nocross=IfCircle(circle->head);
circle->tail->next=circle->head->next->next->next;//构造一个环
node *cross=IfCircle(circle->head);
//7+8-两个单链表是否相交？求交点
LinkInfo *A=CreateInfoFromArray(a1,5);//测试：1-不交叉 2- 交叉 3- 空链表
LinkInfo *B=CreateInfoFromArray(b1,3);
node *nointersection1=Intersection1(A->head,B->head);
node *nointersection2=Intersection2(A->head,B->head);//NULL
B->tail->next=A->head->next->next->next;//设置交叉点在4
node *intersection1=Intersection1(A->head,B->head);
node *intersection2=Intersection1(A->head,B->head);// 4
//9-单链表排序
int s[10]={54,41,32,1,6,4,54,32,658,2};
LinkInfo *linksort=CreateInfoFromArray(s,10);
LinkSortQ(linksort,0);
//10-删除重复元素
DelRepeated(linksort);
//11-拆分链表
LinkInfo *odd=CreateLinkInfo();
LinkInfo *even=CreateLinkInfo();
SplitList(L,odd,even);
//12-大整数加法
char numa[]="-7987465413213546465461111111111";
char numb[]="-574968465216352468749611";
char* result=BigNum(numa,numb);
return 0;
}
//相除
void BigNum::div(BigNum& otherNum)
{
if (this->cmp(otherNum)<0)
{
*this = BigNum(0);
}
else if (this->cmp(otherNum) == 0)
{
*this = BigNum(1);
}
else
{
BigNum resultNum(1);
this->sub(otherNum);
while (this->cmp(otherNum) >= 0)
{
this->sub(otherNum);
++resultNum;
}
*this = resultNum;
}
}
uint8_t BigNum::smallDivide(BigNum const& devider) {
int16_t low = 0;
int16_t high = (1 << 8) - 1;
while (low <= high) {
uint8_t mid = (low + high) >> 1;
if (operator<(devider * BigNum(mid)))
//low = high + 1
//divider * high <= dividend < divider * (high + 1)
high = (int16_t) mid - 1;
else
low = (int16_t) mid + 1;
}
return (uint8_t) high;
}
BigNum BigNum::exponent(long long const& exp, BigNum const& modulus) const {
if (exp == 0)
return BigNum(1);
BigNum result(this->exponent(exp >> 1, modulus));
//square result here
result = result * result;
if (modulus != 0)
result = result % modulus;
if (exp bitand 1) { //odd
result = result * *this;
if (modulus != 0)
result = result % modulus;
}
return result;
}
Vector2 Vector2::operator/(BigNum d)
{
return (*this) * Vector2(BigNum(1)/d, BigNum(1)/d);
}
Vector2 Vector2::operator/(Vector2 v)
{
return (*this) * Vector2(BigNum(1)/v.x, BigNum(1)/v.y);
}
BigNum BigNum::fromBase64(const std::vector<unsigned char> &b64)
{
return BigNum(Base64::decode(b64));
}