TLE + WA 求调 QWQ QAQ Q_Q 必关

#include<iostream>
#include<algorithm>
using namespace std;
int l, r, L, R, k;
bool iswavingnumber(string x) {
    if (x.size() == 1) return true;
    if (x.size() % 2 == 1) x += x[1];
    for (int i = 2; i + 1 < x.size(); i += 2)
        if (x.substr(i - 2, 2) != x.substr(i, 2) || x[i] == x[i + 1])
            return false;
    return true;
}
string basechanging(int x, int base) {
    string ret;
    while (x) {
        if (x % base < 10)
            ret += x % base + '0';
        else
            ret += x % base - 10 + 'A';
        x /= base;
    }
    reverse(ret.begin(), ret.end());
    return ret;
}
int main() {
    cin >> l >> r >> L >> R >> k;
    for (int i = L; i <= R; i++) {
        int cnt = 0;
        for (int j = l; j <= r; j++)
            if (iswavingnumber(basechanging(i, j)))
                cnt++;
        if (cnt == k) cout << i << endl;
    }
    return 0;
}