Problem p02720 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
// #pragma GCC optimize("Ofast")
// #define _GLIBCXX_DEBUG
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
#define int ll
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef pair<int, int> pii;
typedef vector<pair<int, int>> vpii;
typedef vector<vector<int>> vvi;
typedef vector<vector<char>> vvc;
typedef vector<vector<string>> vvs;
typedef vector<vector<ll>> vvll;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define irep(it, stl) for (auto it = stl.begin(); it != stl.end(); it++)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define fin(ans) cout << (ans) << '\\n'
#define mp(p, q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define floatprec(dig) fixed << setprecision(dig)
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define MATHPI acos(-1)
#define itn int;
#define invar(typ, var)                                                        \\
  typ var;                                                                     \\
  cin >> var;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct io {
  io() {
    ios::sync_with_stdio(false);
    cin.tie(0);
  }
};
const int INF = INT_MAX / 2;
const ll LLINF = 1LL << 60;
constexpr ll MOD = 1000000007;
const double EPS = 1e-9;

signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll K;
  cin >> K;

  if (K == 1) {
    fin(1);
    return 0;
  }
  ll ct = 0;

  queue<ll> q;
  rep(i, 9) q.push(i + 1);
  ll num;
  while (true) {
    ll x = q.front();
    q.pop();
    if (x % 10 != 0)
      q.push(x * 10 + (x % 10 - 1));
    q.push(x * 10 + x % 10);
    if (x % 10 != 9)
      q.push(x * 10 + x % 10 + 1);
    num = x;
    ct++;

    if (ct >= K)
      break;
  }

  fin(num);
}

// 16 4 3
/*
1234567890123456
ooxxoxoxxxoxoxxo

5 2 3
12345
ooxoo
00001
*/
//
/*
11 3 2
12345678901
ooxxxoxxxoo
00000111122
12222666601
<- up時のo = 最後のoより後．= 最後のoを記録できる
v.s. 貪欲


*/

Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
// #pragma GCC optimize("Ofast")
// #define _GLIBCXX_DEBUG
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
#define int ll
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef pair<int, int> pii;
typedef vector<pair<int, int>> vpii;
typedef vector<vector<int>> vvi;
typedef vector<vector<char>> vvc;
typedef vector<vector<string>> vvs;
typedef vector<vector<ll>> vvll;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define irep(it, stl) for (auto it = stl.begin(); it != stl.end(); it++)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define fin(ans) cout << (ans) << '\\n'
#define mp(p, q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define floatprec(dig) fixed << setprecision(dig)
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define MATHPI acos(-1)
#define itn int;
#define invar(typ, var)                                                        \\
  typ var;                                                                     \\
  cin >> var;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct io {
  io() {
    ios::sync_with_stdio(false);
    cin.tie(0);
  }
};
const int INF = INT_MAX / 2;
const ll LLINF = 1LL << 60;
constexpr ll MOD = 1000000007;
const double EPS = 1e-9;

bool islun(ll n, int &keta) {
  int p = n % 10;
  n /= 10;
  int i = 0;
  while (n) {
    if (abs(n % 10 - p) > 1) {
      keta = i;
      return false;
    }
    i++;

    n /= 10;
  }
  keta = -1;
  return true;
}

void nextlun(ll &on) {
  on++;
  while (true) {
    int n = on;
    int p = n % 10;
    n /= 10;
    int i = 0;
    int pow1 = 1;
    bool f = false;
    while (n) {
      if (abs(n % 10 - p) > 1) {
        on = (n + 1) * pow1 * 10;
        int ii = 0;
        while (n - ii >= 0) {
          on += (n - ii) * pow1;
          pow1 /= 10;
          ii++;
        }
        f = true;
        break;
      }
      i++;

      pow1 *= 10;
      n /= 10;
    }

    if (!f)
      return;
  }
}

signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll K;
  cin >> K;

  if (K == 1) {
    fin(1);
    return 0;
  }
  ll ct = 1;
  ll num = 1;

  while (true) {
    nextlun(num);
    ct++;

    if (ct >= K)
      break;
  }

  fin(num);
}
// 16 4 3
/*
1234567890123456
ooxxoxoxxxoxoxxo

5 2 3
12345
ooxoo
00001
*/
//
/*
11 3 2
12345678901
ooxxxoxxxoo
00000111122
12222666601
<- up時のo = 最後のoより後．= 最後のoを記録できる
v.s. 貪欲


*/