题解 | #进制转换#

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


void div(vector<int>& A, int b, vector<int>& res) {
    int r = 0;
    vector<int> C;
    for (int i = 0; i < A.size(); i++) {
        r = r * 10 + A[i];
        C.push_back(r / b);
        r %= b;
    }
//    for(int i=0;i<C.size();i++) cout<<C[i];
//  cout<<endl;
//去除前导零
    vector<int> temp;
    int i = 0;
    for (; i < C.size(); i++) {
        if (C[i] != 0) break;
    }
    if (i == C.size()) temp.push_back(0);
    for (; i < C.size(); i++) temp.push_back(C[i]);
    res.push_back(r);//存放每一次除法的余数
    A = temp;
}

int main() {
    string a;
    while (cin >> a) {
        vector<int> A;
        vector<int> res;
        if (a.size() == 1 && a[0] == '0') res.push_back(0);
        for (int i = 0; i < a.size(); i++) A.push_back(a[i] - '0');
        while (A.size() >= 1) {
            if (A.size() == 1 && A[0] == 0)
                break;
            else div(A, 2, res);
        }
        for (int i = res.size() - 1; i >= 0; i--) cout << res[i];
        cout << endl;
    }
    return 0;
}
// 64 位输出请用 printf("%lld")