高精度加减乘除模板 c++

高精度加法

#include<iostream>
#include<vector>
using namespace std;

vector<int> add(vector<int> &A,vector<int> &B){
    vector<int> C;
    int t=0;
    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;
}

int main(){
    vector<int> A,B;
    string a,b;
    cin>>a>>b;
    for(int i=a.size()-1;i>=0;i--) A.push_back(a[i]-'0');
    for(int i=b.size()-1;i>=0;i--) B.push_back(b[i]-'0');
    vector<int> C=add(A,B);
    for(int i=C.size()-1;i>=0;i--) cout<<C[i];
}

高精度减法

#include<iostream>
#include<vector>
using namespace std;


//A>=B?
bool cmp(vector<int> &A,vector<int> &B){
    if(A.size()!=B.size())  return A.size()>B.size();
    for(int i = A.size()-1;i>=0; i--){
        if(A[i]!=B[i])  return A[i]>B[i];
    }
    return true; //equal
}

//if A>=B  do sub
vector<int> sub(vector<int> &A,vector<int> &B){
    vector<int> C;
    for(int i=0,t=0;i<A.size();i++){ //只到A最后一个，因为减的时候默认A>=B
        t=A[i]-t;
        if(i<B.size()) t-=B[i];
        C.push_back((t+10)%10); //重点记忆将t>0,和<=0情况合并
        if(t<0) t=1;
        else t=0;
    }
    //去除首部0
    while(C.size()>1 && C.back()==0)   C.pop_back();
    return C;
    
}

int main(){
    string a,b;
    cin>>a>>b;
    vector<int> A,B;
    
    for(int i=a.size()-1;i>=0;i--)  A.push_back(a[i]-'0');
    for(int i=b.size()-1;i>=0;i--)  B.push_back(b[i]-'0');
 
   // cout<<cmp(A,B)<<endl;
    
    if(cmp(A,B)){
        auto C = sub(A,B);
        for(int i=C.size()-1;i>=0;i--)    cout<<C[i];
        return 0;
    }else{
        auto C= sub(B,A);
        cout<<"-";
        for(int i=C.size()-1;i>=0;i--)    cout<<C[i];
        return 0;
    }
}

高精度乘

#include <iostream>
#include <vector>

using namespace std;


vector<int> mul(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;
    }

    while (C.size() > 1 && C.back() == 0) C.pop_back();

    return C;
}


int main()
{
    string a;
    int b;

    cin >> a >> b;

    vector<int> A;
    for (int i = a.size() - 1; i >= 0; i -- ) A.push_back(a[i] - '0');

    auto C = mul(A, b);

    for (int i = C.size() - 1; i >= 0; i -- ) printf("%d", C[i]);

    return 0;
}

高精度除

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

vector<int> div(vector<int> &A, int b, int &r)
{
    vector<int> C;
    r = 0;
    for (int i = A.size() - 1; i >= 0; i -- )
    {
        r = r * 10 + A[i];
        C.push_back(r / b);
        r %= b;
    }
    reverse(C.begin(), C.end());
    while (C.size() > 1 && C.back() == 0) C.pop_back();
    return C;
}

int main()
{
    string a;
    vector<int> A;

    int B;
    cin >> a >> B;
    for (int i = a.size() - 1; i >= 0; i -- ) A.push_back(a[i] - '0');

    int r;
    auto C = div(A, B, r);

    for (int i = C.size() - 1; i >= 0; i -- ) cout << C[i];

    cout << endl << r << endl;

    return 0;
}