Problem p03212 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <algorithm>
#include <bitset>
#include <ciso646>
#include <cmath>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 1000000007;
typedef long double ld;
const ll INF = 1e+14;
typedef pair<int, int> P;
#define stop                                                                   \
  char nyaa;                                                                   \
  cin >> nyaa;
#define rep(i, n) for (int i = 0; i < n; i++)
#define per(i, n) for (int i = n - 1; i >= 0; i--)
#define Rep(i, sta, n) for (int i = sta; i < n; i++)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define per1(i, n) for (int i = n; i >= 1; i--)
#define Rep1(i, sta, n) for (int i = sta; i <= n; i++)
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ld, ld> LDP;
typedef pair<ll, ll> LP;
#define fr first
#define sc second

void Yes() {
  cout << "Yes" << endl;
  exit(0);
}

void No() {
  cout << "No" << endl;
  exit(0);
}
ll sft[3] = {3, 5, 7};

ll N;

bool check(ll x) {
  set<ll> s;
  while (x > 0) {
    ll k = x % 10;
    s.insert(k);
    x /= 10;
  }
  if (s.size() == 3)
    return true;
  return false;
}

int dfs(ll x) {
  ll res = 0;
  if (check(x))
    res++;
  rep(i, 3) {
    int y = x * 10 + sft[i];
    if (y <= N) {
      res += dfs(y);
    }
  }
  return res;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> N;
  ll ans = dfs(0);
  cout << ans << endl;
  return 0;
}

Fixed submission:
#include <algorithm>
#include <bitset>
#include <ciso646>
#include <cmath>
#include <complex>
#include <cstdio>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 1000000007;
typedef long double ld;
const ll INF = 1e+14;
typedef pair<int, int> P;
#define stop                                                                   \
  char nyaa;                                                                   \
  cin >> nyaa;
#define rep(i, n) for (int i = 0; i < n; i++)
#define per(i, n) for (int i = n - 1; i >= 0; i--)
#define Rep(i, sta, n) for (int i = sta; i < n; i++)
#define rep1(i, n) for (int i = 1; i <= n; i++)
#define per1(i, n) for (int i = n; i >= 1; i--)
#define Rep1(i, sta, n) for (int i = sta; i <= n; i++)
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ld, ld> LDP;
typedef pair<ll, ll> LP;
#define fr first
#define sc second

void Yes() {
  cout << "Yes" << endl;
  exit(0);
}

void No() {
  cout << "No" << endl;
  exit(0);
}
ll sft[3] = {3, 5, 7};

ll N;

bool check(ll x) {
  set<ll> s;
  while (x > 0) {
    ll k = x % 10;
    s.insert(k);
    x /= 10;
  }
  if (s.size() == 3)
    return true;
  return false;
}

int dfs(ll x) {
  ll res = 0;
  if (check(x))
    res++;
  rep(i, 3) {
    ll y = x * 10 + sft[i];
    if (y <= N) {
      res += dfs(y);
    }
  }
  return res;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> N;
  ll ans = dfs(0);
  cout << ans << endl;
  return 0;
}