25pts #4 AC,求助，本地通过

#include<bits/stdc++.h>
using namespace std;
char q[17] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
string o;

bool huiwen(string m) {
    for (int i = 0; i < m.length() / 2; i++) {
        if (m[i] != m[m.length() - 1 - i]) {
            return 0;
        }
    }
    return 1;
}

string swaps(string q) {
    for (int i = 0; i < q.length() / 2; i++) {
        swap(q[i], q[q.length() - 1 - i]);
    }
    return q;
}

string add(string a, string b, int k) {
    int numa[105], numb[105], numc[105];
    int len = a.length(), lenc = 1;
    string ans;
    for (int i = 0; i < len; i++) {
        if (isdigit(a[i])) numa[len - i] = a[i] - '0';
        else numa[len - i] = a[i] - 'A' + 10;
        if (isdigit(b[i])) numb[len - i] = b[i] - '0';
        else numb[len - i] = b[i] - 'A' + 10;
    }
    int x = 0;
    while (lenc <= len) {
        numc[lenc] = numa[lenc] + numb[lenc] + x;
        x = numc[lenc] / k;
        numc[lenc] %= k;
        lenc++;
    }
    numc[lenc] = x;
    while (numc[lenc] == 0) lenc--;
    for (int i = lenc; i >= 1; i--) ans += q[numc[i]];
    return ans;
}

int main() {
    int jw;
    cin >> jw;
    cin >> o;
    for (int i = 1; i <= 31; i++) {
        if (huiwen(o)) {
            cout << i - 1;
            return 0;
        }
        if (i == 31) {
            cout << "Impossible!";
            return 0;
        }
        o = add(swaps(o), o, jw);
    }
    return 0;
}