$\huge \color{orange}{成仙之路->}$ $\huge \color{purple}{算法基础课题解}$

完整代码

#include<bits/stdc++.h>

using namespace std;

vector<int> mul(vector<int> &A,int b) //计算 A * b
{
    vector<int> C;
    for(int i=0,t=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()) C.pop_back();
    return C;
}

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

    cin>>a>>b;

    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--) cout<<C[i];

    return 0;
}