进位运算的高精度写法

原理是把高精度除法的乘数从10变成a,循环直至数组A变为长度为1的0则break

这题的输出格式有点坑，不用特判 T==0 的情况输不输出换行

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

typedef long long LL;
int T;

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

int main(){
    cin >> T;
    while(T--){
        string sa;
        int a,b;
        cin >> a >> b >> sa;
        vector<int> A,B;
        for(int i = sa.size()-1; i >= 0; i--){
            if(sa[i] >= '0' && sa[i] <= '9')A.push_back(sa[i]-'0');
            if(sa[i] >= 'a' && sa[i] <= 'z')A.push_back(sa[i]-'a'+36);
            if(sa[i] >= 'A' && sa[i] <= 'Z')A.push_back(sa[i]-'A'+10);
        }

        while(true){
            LL r;
            A = div(A,a,b,r);
            B.push_back(r);
            if(A.size()==1 && A[0] == 0)break;
        }
        cout << a << " " << sa << endl;
        cout << b << " ";
        for(int i = B.size()-1; i >= 0; i--){
            char c = B[i];
            if(c >= 0 && c <= 9) c += '0';
            else if(c >= 36 && c <= 61) c += 'a'-36;
            else if(c >= 10 && c <= 35) c += 'A'-10;
            cout << c;
        }
        cout << endl;
        cout << endl;
    }
    return 0;
}