Problem p01209 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>

#define _overload(_1, _2, _3, name, ...) name
#define _rep(i, n) _range(i, 0, n)
#define _range(i, a, b) for (int i = int(a); i < int(b); ++i)
#define rep(...) _overload(__VA_ARGS__, _range, _rep, )(__VA_ARGS__)

#define _rrep(i, n) _rrange(i, n, 0)
#define _rrange(i, a, b) for (int i = int(a) - 1; i >= int(b); --i)
#define rrep(...) _overload(__VA_ARGS__, _rrange, _rrep, )(__VA_ARGS__)

#define _all(arg) begin(arg), end(arg)
#define uniq(arg) sort(_all(arg)), (arg).erase(unique(_all(arg)), end(arg))
#define getidx(ary, key) lower_bound(_all(ary), key) - begin(ary)
#define clr(a, b) memset((a), (b), sizeof(a))
#define bit(n) (1LL << (n))

template <class T> bool chmax(T &a, const T &b) {
  return (a < b) ? (a = b, 1) : 0;
}
template <class T> bool chmin(T &a, const T &b) {
  return (b < a) ? (a = b, 1) : 0;
}

using namespace std;
using ll = long long;

ll convert(char c) {
  if (isdigit(c))
    return c - '0';
  else
    return c - 'A' + 10;
}

const int prime[11] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31};

int main(void) {
  ll n;
  string m;
  while (cin >> n >> m, n) {
    ll num[11] = {0};
    ll mten = 0LL;

    for (auto &d : m)
      mten = n * mten + convert(d);
    rep(i, 11) {
      ll cur = prime[i];
      while (cur < mten)
        num[i] += mten / cur, cur *= prime[i];
    }
    ll ans = -1LL;
    rep(i, 11) {
      ll cur = n, coef = 0LL;
      while (cur % prime[i] == 0)
        cur /= prime[i], coef++;
      if (coef == 0)
        continue;
      if (ans == -1)
        ans = num[i] / coef;
      else
        chmin(ans, num[i] / coef);
    }
    cout << ans << endl;
  }
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>

#define _overload(_1, _2, _3, name, ...) name
#define _rep(i, n) _range(i, 0, n)
#define _range(i, a, b) for (int i = int(a); i < int(b); ++i)
#define rep(...) _overload(__VA_ARGS__, _range, _rep, )(__VA_ARGS__)

#define _rrep(i, n) _rrange(i, n, 0)
#define _rrange(i, a, b) for (int i = int(a) - 1; i >= int(b); --i)
#define rrep(...) _overload(__VA_ARGS__, _rrange, _rrep, )(__VA_ARGS__)

#define _all(arg) begin(arg), end(arg)
#define uniq(arg) sort(_all(arg)), (arg).erase(unique(_all(arg)), end(arg))
#define getidx(ary, key) lower_bound(_all(ary), key) - begin(ary)
#define clr(a, b) memset((a), (b), sizeof(a))
#define bit(n) (1LL << (n))

template <class T> bool chmax(T &a, const T &b) {
  return (a < b) ? (a = b, 1) : 0;
}
template <class T> bool chmin(T &a, const T &b) {
  return (b < a) ? (a = b, 1) : 0;
}

using namespace std;
using ll = long long;

ll convert(char c) {
  if (isdigit(c))
    return c - '0';
  else
    return c - 'A' + 10;
}

const int prime[11] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31};

int main(void) {
  ll n;
  string m;
  while (cin >> n >> m, n) {
    ll num[11] = {0};
    ll mten = 0LL;

    for (auto &d : m)
      mten = n * mten + convert(d);
    rep(i, 11) {
      ll cur = prime[i];
      while (1) {
        num[i] += mten / cur;
        if (cur > mten / prime[i])
          break;
        cur *= prime[i];
      }
    }
    ll ans = -1LL;
    rep(i, 11) {
      ll cur = n, coef = 0LL;
      while (cur % prime[i] == 0)
        cur /= prime[i], coef++;
      if (coef == 0)
        continue;
      if (ans == -1)
        ans = num[i] / coef;
      else
        chmin(ans, num[i] / coef);
    }
    cout << ans << endl;
  }
  return 0;
}