Problem p02588 (C++) — buggy submission, verdict: Runtime Error

///////////////////////////////////////////////////////////////////////////////

#include <bits/stdc++.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>

using namespace std;

///////////////////////////////////////////////////////////////////////////////

#define DEBUG 0

#define pb push_back
#define V vector
#define M unordered_map
#define S static

#define rep(i, n) for (ll i = 0LL; i < n; ++i)
#define srep(i, s, n) for (ll i = s; i < n; ++i)
#define rrep(i, n) for (ll i = n - 1LL; i >= 0LL; --i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define CIN(x)                                                                 \\
  do {                                                                         \\
    assert(!cin.eof());                                                        \\
    cin >> x;                                                                  \\
    assert(!cin.fail());                                                       \\
  } while (0);
#if DEBUG
#define debug_print(...) _debug_print(__VA_ARGS__)
#define debug_printf(...) printf(__VA_ARGS__)
#define debug_print_time _debug_print_time
#else // DEBUG
#define debug_print(...)
#define debug_printf(...)
#define debug_print_time
#endif // DEBUG

typedef long long ll;
typedef unsigned long long ull;
typedef tuple<ll, ll> t2;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, ll, ll> t4;
typedef tuple<ll, ll, ll, ll, ll> t5;
template <typename T>
using priority_queue_incr = priority_queue<T, V<T>, greater<T>>;

///////////////////////////////////////////////////////////////////////////////

template <typename TT, typename T> T get_m(M<TT, T> &m, TT k, T default_value) {
  if (m.find(k) == m.end())
    return m[k] = default_value;
  return m[k];
}

template <typename TT, typename T> void incr_m(M<TT, T> &m, TT k) {
  if (m.find(k) == m.end())
    m[k] = 0;
  m[k]++;
}

template <typename TT, typename T> void incr_m(map<TT, T> &m, TT k) {
  if (m.find(k) == m.end())
    m[k] = 0;
  m[k]++;
}

void llin(ll &a) { CIN(a); }

void llinl1(V<ll> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a;
    CIN(a);
    v.push_back(a);
  }
}

void llinl2(V<t2> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a, b;
    CIN(a >> b);
    v.push_back(t2(a, b));
  }
}

void llinl3(V<t3> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a, b, c;
    CIN(a >> b >> c);
    v.push_back(t3(a, b, c));
  }
}

void llinl4(V<t4> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a, b, c, d;
    CIN(a >> b >> c >> d);
    v.push_back(t4(a, b, c, d));
  }
}

void llina(V<ll> &v, ll count) { llinl1(v, count); }

template <typename T> void sort(V<T> &v) { sort(v.begin(), v.end()); }

template <typename T> void sort_reverse(V<T> &v) {
  sort(v.begin(), v.end(), greater<T>());
}

template <typename T> void _debug_print(T x) { cout << x << endl; }

void _debug_print(const t2 &x) {
  ll x1 = get<0>(x);
  ll x2 = get<1>(x);
  cout << "-- " << x1 << " -- " << x2 << endl;
}

void _debug_print(const t3 &x) {
  ll x1 = get<0>(x);
  ll x2 = get<1>(x);
  ll x3 = get<2>(x);
  cout << "-- " << x1 << " -- " << x2 << " -- " << x3 << endl;
}

void _debug_print(const t4 &x) {
  ll x1 = get<0>(x);
  ll x2 = get<1>(x);
  ll x3 = get<2>(x);
  ll x4 = get<3>(x);
  cout << "-- " << x1 << " -- " << x2 << " -- " << x3 << " -- " << x4 << endl;
}

template <typename T> void _debug_print(T xarray[], ll n) {
  rep(i, n) _debug_print(xarray[i]);
}

template <typename T> void _debug_print(const V<T> &xlist) {
  for (auto x : xlist) {
    cout << "-- ";
    _debug_print(x);
  }
}

template <typename T> void _debug_print(const set<T> &xset) {
  for (auto x : xset) {
    cout << "-- ";
    _debug_print(x);
  }
}

template <typename TT, typename T> void _debug_print(const M<TT, T> &xlist) {
  for (auto x : xlist) {
    TT k = x.first;
    T v = x.second;
    cout << "====" << endl;
    cout << "K=";
    _debug_print(k);
    cout << "V=";
    _debug_print(v);
  }
}

template <typename TT, typename T> void _debug_print(const map<TT, T> &xlist) {
  for (auto x : xlist) {
    TT k = x.first;
    T v = x.second;
    cout << "====" << endl;
    cout << "K=";
    _debug_print(k);
    cout << "V=";
    _debug_print(v);
  }
}

void _debug_print_time(const char *prefix) {
  struct timeval tv;
  gettimeofday(&tv, NULL);
#if DEBUG
  struct tm *tm = localtime(&tv.tv_sec);
#endif
  debug_printf("-- %s %02d:%02d:%02d.%06ld\\n", prefix, tm->tm_hour, tm->tm_min,
               tm->tm_sec, tv.tv_usec);
}

template <typename T> struct SegmentTree {
  T *nodes;
  t2 *ranges; // [start, end)
  ll nodecount;
  ll itemcount;
  T unit;
  T (*op)(T, T);

  SegmentTree(ll itemcount, T unit, T op(T, T)) {
    ll orig_itemcount = itemcount;
    this->itemcount = 1LL;
    while (this->itemcount < orig_itemcount)
      this->itemcount *= 2LL;
    nodecount = this->itemcount * 2 - 1;
    nodes = new T[nodecount];
    ranges = new t2[nodecount];
    this->unit = unit;
    this->op = op;

    ll start = 0LL;
    ll end = this->itemcount;
    ll len = this->itemcount;

    rep(i, nodecount) {
      nodes[i] = unit;
      ranges[i] = t2(start, end);
      if (end >= this->itemcount) {
        len /= 2LL;
        start = 0LL;
        end = len;
      } else {
        start = end;
        end = start + len;
      }
    }
  }

  void build(const T arr[]) {
    memcpy(nodes + nodecount / 2LL, arr, sizeof(T) * itemcount);
    rrep(i, nodecount / 2LL) {
      nodes[i] = op(nodes[i * 2LL + 1LL], nodes[i * 2LL + 2LL]);
    }
  }

  void update(ll k, T v) {
    ll idx = k + itemcount - 1LL;
    nodes[idx] = v;
    idx = (idx - 1LL) / 2LL;

    for (; idx >= 0; idx = (idx - 1LL) / 2LL) {
      nodes[idx] = op(nodes[idx * 2LL + 1LL], nodes[idx * 2LL + 2LL]);
      if (!idx)
        break;
    }
  }

  // query to [start, end)
  virtual T query(ll start, ll end) const { return _query(start, end, 0LL); }

  virtual T _query(ll start, ll end, ll idx) const {
    ll rstart = get<0>(ranges[idx]);
    ll rend = get<1>(ranges[idx]);

    if (start <= rstart && rend <= end) {
      return nodes[idx];
    }
    if (rend <= start || end <= rstart) {
      return unit;
    }
    T left = _query(start, end, idx * 2LL + 1LL);
    T right = _query(start, end, idx * 2LL + 2LL);
    return op(left, right);
  }

  T query_fast(ll start, ll end) const {
    start += nodecount / 2LL;
    end += nodecount / 2LL;
    T lval = unit;
    T rval = unit;
    for (; start < end; start >>= 1LL, end >>= 1LL) {
      if (!(start & 1LL))
        lval = op(lval, nodes[start]);
      if (!(end & 1LL))
        rval = op(rval, nodes[end - 1]);
      end--;
    }
    return op(lval, rval);
  }
};

//// update : sum / query : range sum
// ll op(ll x, ll y){ return x + y; }
// void op_upd(ll &x, ll y) { x += y; }
// ll op_div(ll x) { return x / 2LL; }
// ll op_mlt(ll x, ll y) { return x * y; }
//// update : sum / query : range max
// ll op(ll x, ll y) { return max(x, y); }
// void op_upd(ll &x, ll y) { x += y; }
// ll op_div(ll x) { return x; }
// ll op_mlt(ll x, ll y) { return x; }
//// update : substitute / query : range sum
// ll add(ll x, ll y) { return x + y; }
// void upd(ll &x, ll y) { x = y; }
// ll div(ll x) { return x / 2LL; }
// ll mlt(ll x, ll y) { return x * y; }
template <typename T> struct SegmentTreeLazy : public SegmentTree<T> {
  T *lzvals;
  bool *lzvalids;
  ll unit_upd;
  void (*op_upd)(T &, T);
  T (*op_div)(T);
  T (*op_mlt)(T, T);

  SegmentTreeLazy(ll itemcount, T unit, T unit_upd, T op(T, T),
                  void op_upd(T &, T), T op_div(T), T op_mlt(T, T))
      : SegmentTree<T>(itemcount, unit, op) {
    this->lzvals = new T[this->nodecount];
    this->lzvalids = new bool[this->nodecount];
    this->unit_upd = unit_upd;
    this->op_upd = op_upd;
    this->op_div = op_div;
    this->op_mlt = op_mlt;
    rep(i, this->nodecount) this->lzvals[i] = unit_upd;
    memset(this->lzvalids, 0, sizeof(bool) * this->nodecount);
  }

  // newval = op_upd(oldval, lzval);
  void eval(ll nodeidx) {
    if (!lzvalids[nodeidx])
      return;

    op_upd(this->nodes[nodeidx], lzvals[nodeidx]);

    if (nodeidx * 2LL + 2LL < this->nodecount) {
      ll downval = op_div(lzvals[nodeidx]);
      op_upd(lzvals[nodeidx * 2LL + 1LL], downval);
      op_upd(lzvals[nodeidx * 2LL + 2LL], downval);
      lzvalids[nodeidx * 2LL + 1LL] = lzvalids[nodeidx * 2LL + 2LL] = true;
    }

    lzvalids[nodeidx] = false;
    lzvals[nodeidx] = this->unit_upd;
  }

  void update(ll start, ll end, ll val) { _update(start, end, val, 0LL); }

  void _update(ll start, ll end, ll val, ll nodeidx) {
    eval(nodeidx);

    ll rstart = get<0>(this->ranges[nodeidx]);
    ll rend = get<1>(this->ranges[nodeidx]);
    if (end <= rstart || rend <= start)
      return;

    if (start <= rstart && rend <= end) {
      op_upd(lzvals[nodeidx], op_mlt(val, rend - rstart));
      lzvalids[nodeidx] = true;
      eval(nodeidx);
    } else {
      _update(start, end, val, nodeidx * 2LL + 1LL);
      _update(start, end, val, nodeidx * 2LL + 2LL);
      this->nodes[nodeidx] = this->op(this->nodes[nodeidx * 2LL + 1LL],
                                      this->nodes[nodeidx * 2LL + 2LL]);
    }
  }

  // query to [start, end)
  virtual T query(ll start, ll end) { return _query(start, end, 0LL); }

  virtual T _query(ll start, ll end, ll nodeidx) {
    ll rstart = get<0>(this->ranges[nodeidx]);
    ll rend = get<1>(this->ranges[nodeidx]);

    eval(nodeidx);

    if (start <= rstart && rend <= end) {
      return this->nodes[nodeidx];
    }
    if (rend <= start || end <= rstart) {
      return this->unit;
    }
    T left = _query(start, end, nodeidx * 2LL + 1LL);
    T right = _query(start, end, nodeidx * 2LL + 2LL);
    return this->op(left, right);
  }
};

///////////////////////////////////////////////////////////////////////////////

void _main();
int main() {
  cout << setprecision(12);
#if !DEBUG
  ios::sync_with_stdio(false);
  cin.tie(0);
#endif

  _main();
  return 0;
}

ll sumll(ll x, ll y) { return x + y; }

void _main() {
  ll n;
  llin(n);
  V<ll> alist;
  rep(i, n) {
    string a;
    CIN(a);
    ll val = 0;
    ll ucnt = 0;
    bool flag = false;
    for (auto c : a) {
      if (c == '.') {
        flag = true;
        continue;
      }
      if (flag)
        ucnt++;
      val *= 10LL;
      val += (ll)(c - '0');
    }
    rep(i, 9LL - ucnt) val *= 10LL;
    alist.pb(val);
  }

  ll cnts[20][20];
  memset(cnts, 0, sizeof(cnts));

  for (auto a : alist) {
    ll cnt2 = 0;
    while (a % 2LL == 0) {
      cnt2++;
      a /= 2LL;
      if (cnt2 >= 18)
        break;
    }
    ll cnt5 = 0;
    while (a % 5LL == 0) {
      cnt5++;
      a /= 5LL;
      if (cnt5 >= 18)
        break;
    }
    cnts[cnt2][cnt5]++;
  }

  ll ans = 0;

  rep(a, 20) rep(b, 20) rep(c, 20) rep(d, 20) {
    if (a + c < 18)
      continue;
    if (b + d < 18)
      continue;
    ans += cnts[a][b] * cnts[c][d];
  }

  srep(a, 9, 20) srep(b, 9, 20) { ans -= cnts[a][b]; }

  ans /= 2LL;

  cout << ans << endl;
}

///////////////////////////////////////////////////////////////////////////////


Error: 0

Fixed submission:

///////////////////////////////////////////////////////////////////////////////

#include <bits/stdc++.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>

using namespace std;

///////////////////////////////////////////////////////////////////////////////

#define DEBUG 0

#define pb push_back
#define V vector
#define M unordered_map
#define S static

#define rep(i, n) for (ll i = 0LL; i < n; ++i)
#define srep(i, s, n) for (ll i = s; i < n; ++i)
#define rrep(i, n) for (ll i = n - 1LL; i >= 0LL; --i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define CIN(x)                                                                 \\
  do {                                                                         \\
    assert(!cin.eof());                                                        \\
    cin >> x;                                                                  \\
    assert(!cin.fail());                                                       \\
  } while (0);
#if DEBUG
#define debug_print(...) _debug_print(__VA_ARGS__)
#define debug_printf(...) printf(__VA_ARGS__)
#define debug_print_time _debug_print_time
#else // DEBUG
#define debug_print(...)
#define debug_printf(...)
#define debug_print_time
#endif // DEBUG

typedef long long ll;
typedef unsigned long long ull;
typedef tuple<ll, ll> t2;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, ll, ll> t4;
typedef tuple<ll, ll, ll, ll, ll> t5;
template <typename T>
using priority_queue_incr = priority_queue<T, V<T>, greater<T>>;

///////////////////////////////////////////////////////////////////////////////

template <typename TT, typename T> T get_m(M<TT, T> &m, TT k, T default_value) {
  if (m.find(k) == m.end())
    return m[k] = default_value;
  return m[k];
}

template <typename TT, typename T> void incr_m(M<TT, T> &m, TT k) {
  if (m.find(k) == m.end())
    m[k] = 0;
  m[k]++;
}

template <typename TT, typename T> void incr_m(map<TT, T> &m, TT k) {
  if (m.find(k) == m.end())
    m[k] = 0;
  m[k]++;
}

void llin(ll &a) { CIN(a); }

void llinl1(V<ll> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a;
    CIN(a);
    v.push_back(a);
  }
}

void llinl2(V<t2> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a, b;
    CIN(a >> b);
    v.push_back(t2(a, b));
  }
}

void llinl3(V<t3> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a, b, c;
    CIN(a >> b >> c);
    v.push_back(t3(a, b, c));
  }
}

void llinl4(V<t4> &v, ll count) {
  for (ll i = 0LL; i < count; ++i) {
    ll a, b, c, d;
    CIN(a >> b >> c >> d);
    v.push_back(t4(a, b, c, d));
  }
}

void llina(V<ll> &v, ll count) { llinl1(v, count); }

template <typename T> void sort(V<T> &v) { sort(v.begin(), v.end()); }

template <typename T> void sort_reverse(V<T> &v) {
  sort(v.begin(), v.end(), greater<T>());
}

template <typename T> void _debug_print(T x) { cout << x << endl; }

void _debug_print(const t2 &x) {
  ll x1 = get<0>(x);
  ll x2 = get<1>(x);
  cout << "-- " << x1 << " -- " << x2 << endl;
}

void _debug_print(const t3 &x) {
  ll x1 = get<0>(x);
  ll x2 = get<1>(x);
  ll x3 = get<2>(x);
  cout << "-- " << x1 << " -- " << x2 << " -- " << x3 << endl;
}

void _debug_print(const t4 &x) {
  ll x1 = get<0>(x);
  ll x2 = get<1>(x);
  ll x3 = get<2>(x);
  ll x4 = get<3>(x);
  cout << "-- " << x1 << " -- " << x2 << " -- " << x3 << " -- " << x4 << endl;
}

template <typename T> void _debug_print(T xarray[], ll n) {
  rep(i, n) _debug_print(xarray[i]);
}

template <typename T> void _debug_print(const V<T> &xlist) {
  for (auto x : xlist) {
    cout << "-- ";
    _debug_print(x);
  }
}

template <typename T> void _debug_print(const set<T> &xset) {
  for (auto x : xset) {
    cout << "-- ";
    _debug_print(x);
  }
}

template <typename TT, typename T> void _debug_print(const M<TT, T> &xlist) {
  for (auto x : xlist) {
    TT k = x.first;
    T v = x.second;
    cout << "====" << endl;
    cout << "K=";
    _debug_print(k);
    cout << "V=";
    _debug_print(v);
  }
}

template <typename TT, typename T> void _debug_print(const map<TT, T> &xlist) {
  for (auto x : xlist) {
    TT k = x.first;
    T v = x.second;
    cout << "====" << endl;
    cout << "K=";
    _debug_print(k);
    cout << "V=";
    _debug_print(v);
  }
}

void _debug_print_time(const char *prefix) {
  struct timeval tv;
  gettimeofday(&tv, NULL);
#if DEBUG
  struct tm *tm = localtime(&tv.tv_sec);
#endif
  debug_printf("-- %s %02d:%02d:%02d.%06ld\\n", prefix, tm->tm_hour, tm->tm_min,
               tm->tm_sec, tv.tv_usec);
}

template <typename T> struct SegmentTree {
  T *nodes;
  t2 *ranges; // [start, end)
  ll nodecount;
  ll itemcount;
  T unit;
  T (*op)(T, T);

  SegmentTree(ll itemcount, T unit, T op(T, T)) {
    ll orig_itemcount = itemcount;
    this->itemcount = 1LL;
    while (this->itemcount < orig_itemcount)
      this->itemcount *= 2LL;
    nodecount = this->itemcount * 2 - 1;
    nodes = new T[nodecount];
    ranges = new t2[nodecount];
    this->unit = unit;
    this->op = op;

    ll start = 0LL;
    ll end = this->itemcount;
    ll len = this->itemcount;

    rep(i, nodecount) {
      nodes[i] = unit;
      ranges[i] = t2(start, end);
      if (end >= this->itemcount) {
        len /= 2LL;
        start = 0LL;
        end = len;
      } else {
        start = end;
        end = start + len;
      }
    }
  }

  void build(const T arr[]) {
    memcpy(nodes + nodecount / 2LL, arr, sizeof(T) * itemcount);
    rrep(i, nodecount / 2LL) {
      nodes[i] = op(nodes[i * 2LL + 1LL], nodes[i * 2LL + 2LL]);
    }
  }

  void update(ll k, T v) {
    ll idx = k + itemcount - 1LL;
    nodes[idx] = v;
    idx = (idx - 1LL) / 2LL;

    for (; idx >= 0; idx = (idx - 1LL) / 2LL) {
      nodes[idx] = op(nodes[idx * 2LL + 1LL], nodes[idx * 2LL + 2LL]);
      if (!idx)
        break;
    }
  }

  // query to [start, end)
  virtual T query(ll start, ll end) const { return _query(start, end, 0LL); }

  virtual T _query(ll start, ll end, ll idx) const {
    ll rstart = get<0>(ranges[idx]);
    ll rend = get<1>(ranges[idx]);

    if (start <= rstart && rend <= end) {
      return nodes[idx];
    }
    if (rend <= start || end <= rstart) {
      return unit;
    }
    T left = _query(start, end, idx * 2LL + 1LL);
    T right = _query(start, end, idx * 2LL + 2LL);
    return op(left, right);
  }

  T query_fast(ll start, ll end) const {
    start += nodecount / 2LL;
    end += nodecount / 2LL;
    T lval = unit;
    T rval = unit;
    for (; start < end; start >>= 1LL, end >>= 1LL) {
      if (!(start & 1LL))
        lval = op(lval, nodes[start]);
      if (!(end & 1LL))
        rval = op(rval, nodes[end - 1]);
      end--;
    }
    return op(lval, rval);
  }
};

//// update : sum / query : range sum
// ll op(ll x, ll y){ return x + y; }
// void op_upd(ll &x, ll y) { x += y; }
// ll op_div(ll x) { return x / 2LL; }
// ll op_mlt(ll x, ll y) { return x * y; }
//// update : sum / query : range max
// ll op(ll x, ll y) { return max(x, y); }
// void op_upd(ll &x, ll y) { x += y; }
// ll op_div(ll x) { return x; }
// ll op_mlt(ll x, ll y) { return x; }
//// update : substitute / query : range sum
// ll add(ll x, ll y) { return x + y; }
// void upd(ll &x, ll y) { x = y; }
// ll div(ll x) { return x / 2LL; }
// ll mlt(ll x, ll y) { return x * y; }
template <typename T> struct SegmentTreeLazy : public SegmentTree<T> {
  T *lzvals;
  bool *lzvalids;
  ll unit_upd;
  void (*op_upd)(T &, T);
  T (*op_div)(T);
  T (*op_mlt)(T, T);

  SegmentTreeLazy(ll itemcount, T unit, T unit_upd, T op(T, T),
                  void op_upd(T &, T), T op_div(T), T op_mlt(T, T))
      : SegmentTree<T>(itemcount, unit, op) {
    this->lzvals = new T[this->nodecount];
    this->lzvalids = new bool[this->nodecount];
    this->unit_upd = unit_upd;
    this->op_upd = op_upd;
    this->op_div = op_div;
    this->op_mlt = op_mlt;
    rep(i, this->nodecount) this->lzvals[i] = unit_upd;
    memset(this->lzvalids, 0, sizeof(bool) * this->nodecount);
  }

  // newval = op_upd(oldval, lzval);
  void eval(ll nodeidx) {
    if (!lzvalids[nodeidx])
      return;

    op_upd(this->nodes[nodeidx], lzvals[nodeidx]);

    if (nodeidx * 2LL + 2LL < this->nodecount) {
      ll downval = op_div(lzvals[nodeidx]);
      op_upd(lzvals[nodeidx * 2LL + 1LL], downval);
      op_upd(lzvals[nodeidx * 2LL + 2LL], downval);
      lzvalids[nodeidx * 2LL + 1LL] = lzvalids[nodeidx * 2LL + 2LL] = true;
    }

    lzvalids[nodeidx] = false;
    lzvals[nodeidx] = this->unit_upd;
  }

  void update(ll start, ll end, ll val) { _update(start, end, val, 0LL); }

  void _update(ll start, ll end, ll val, ll nodeidx) {
    eval(nodeidx);

    ll rstart = get<0>(this->ranges[nodeidx]);
    ll rend = get<1>(this->ranges[nodeidx]);
    if (end <= rstart || rend <= start)
      return;

    if (start <= rstart && rend <= end) {
      op_upd(lzvals[nodeidx], op_mlt(val, rend - rstart));
      lzvalids[nodeidx] = true;
      eval(nodeidx);
    } else {
      _update(start, end, val, nodeidx * 2LL + 1LL);
      _update(start, end, val, nodeidx * 2LL + 2LL);
      this->nodes[nodeidx] = this->op(this->nodes[nodeidx * 2LL + 1LL],
                                      this->nodes[nodeidx * 2LL + 2LL]);
    }
  }

  // query to [start, end)
  virtual T query(ll start, ll end) { return _query(start, end, 0LL); }

  virtual T _query(ll start, ll end, ll nodeidx) {
    ll rstart = get<0>(this->ranges[nodeidx]);
    ll rend = get<1>(this->ranges[nodeidx]);

    eval(nodeidx);

    if (start <= rstart && rend <= end) {
      return this->nodes[nodeidx];
    }
    if (rend <= start || end <= rstart) {
      return this->unit;
    }
    T left = _query(start, end, nodeidx * 2LL + 1LL);
    T right = _query(start, end, nodeidx * 2LL + 2LL);
    return this->op(left, right);
  }
};

///////////////////////////////////////////////////////////////////////////////

void _main();
int main() {
  cout << setprecision(12);
#if !DEBUG
  ios::sync_with_stdio(false);
  cin.tie(0);
#endif

  _main();
  return 0;
}

ll sumll(ll x, ll y) { return x + y; }

void _main() {
  ll n;
  llin(n);
  V<ll> alist;
  rep(i, n) {
    double tmp;
    CIN(tmp);
    alist.pb((ll)(tmp * 1e9));
  }

  ll cnts[20][20];
  memset(cnts, 0, sizeof(cnts));

  for (auto a : alist) {
    ll cnt2 = 0;
    while (a % 2LL == 0) {
      cnt2++;
      a /= 2LL;
    }
    ll cnt5 = 0;
    while (a % 5LL == 0) {
      cnt5++;
      a /= 5LL;
    }
    cnts[cnt2][cnt5]++;
  }

  ll ans = 0;

  rep(a, 20) rep(b, 20) rep(c, 20) rep(d, 20) {
    if (a + c < 18)
      continue;
    if (b + d < 18)
      continue;
    ans += cnts[a][b] * cnts[c][d];
  }

  srep(a, 9, 20) srep(b, 9, 20) { ans -= cnts[a][b]; }

  ans /= 2LL;

  cout << ans << endl;
}

///////////////////////////////////////////////////////////////////////////////