算法2

4.二分算法（浮点数)
bool check(double x).....//x满足某种性质
void bsearch_3(double l,double r)
{
const eps=1e-6;//控制精度
while(i-j<eps)
{
int mid=(l+r)/2;
if(check(mid))l=mid;
r=mid;
}
5.高精度加法
vector<int>add(vector<int>&A,vector<int>&B)
{
int t=0;
vector<int>c;
for(int i=0;i<A.size()||i<B.size();i++)
{
if(i<A.size()) t+=A[i];
if(i<B.size()) t+=B[i];
c.push_back(t%10);
t/=10;
}
if(t)c.push_back(1);
return c;
}
6.高精度减法
vector<int>cmp(vector<int>&A,vector<int>&B)//比较A和B大小
{
if(A.size()!=B.size())return A.size()>.size();
else
{
for(int i=0;i<a.size();i++)
if(A[i]!=B[i])return A[i]>B[i];
else return true;
}
}
vector<int>sub(vector<int>&A,vector<int>&B)
{vector<int>c;
for(int i=0,t=0;i<A.size();i++)//默认A>B
{
t=A[i]-t;
if(i<B.size())t-=B[i];
c.push_back((t+10)%10);
t/=10;
}
if(c.size()>1&&c.back()==0)c.pop_back();
return c;
}
7.高精度乘法
vector<int>mcl(vector<int>&A,int b)
{
vector<int>c;
int t=0;
for(int i=0;i<A.size()||t;i++)
{
if(i<A.size())t=A[i]*b;
c.push_back(t%10);
t/=10;
}
if(c.size()>1&&c.back()==0)c.pop_back();
return c;
}
8.高精度除法
vector<int>mcl(vector<int>&A,int b,int &r)
{
r=0;
for(int i=A.size()-1;i>=0;i--)
{
r=10*r+A[i];
c.push_back(r/b);
c%=b;
}
reserve(c.begin(),c.end());
if(c.size()>1&&c.back()==0)c.pop_back();
return c;
}