Submission #630138

#	Time	Username	Problem	Language	Result	Execution time	Memory
630138		coloboxx	Palindrome-Free Numbers (BOI13_numbers)	C++17	85 / 100	44 ms	740 KiB

numbers

#include<bits/stdc++.h>

#define ll long long
#define ld long double
#define fi first
#define sc second
#define pb push_back
#define point pair<int,int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define fast_io ios_base::sync_with_stdio(0); cin.tie(0);
#define show(x) cerr << (#x) << " = " << x << '\n'
#define print(x) if (1) {cerr << (#x) << " = "; \
      for (auto it : x) cerr << it << ' '; cerr << '\n';}

using namespace std;

const int MAXN = 1000069;
const int MAXT = 1e7 + 69;
const int RT = 420;
const int LOG = 31;
const int MOD = 998244353;
const int INF = 2e9 + 69;
const ll MAX = 2e18 + 69;
const ld EPS = 1e-12;

#define int ll

ll dp[20][11][11][11][2];

bool check(ll n, int addlen = 0) {
	string s = to_string(n);
	while (s.size() < addlen)
		s = "0" + s;

	for (int i = 1; i < s.size(); ++i)
		if (s[i] == s[i - 1])
			return false;

	for (int i = 2; i < s.size(); ++i)
		if (s[i] == s[i - 2])
			return false;
	
	return true;
}

ll f(ll n) {
	if (n <= 1e6) {
		ll ans = 0;
		for (int i = 0; i <= n; ++i)
			ans += check(i);
		return ans;
	}
	
	for (int i = 0; i < 20; ++i)
		for (int j = 0; j < 11; ++j)
			for (int k = 0; k < 11; ++k)
				for (int l = 0; l < 11; ++l) 
					dp[i][j][k][l][0] = dp[i][j][k][l][1] = 0;
	
	string s = to_string(n);
	reverse(all(s)), s = "0" + s;

	for (auto& c : s)
		c -= '0';

	for (int i = 0; i < 1000; ++i) {
		if (check(i, 3)) {
			dp[3][i / 100][i / 10 % 10][i % 10][0] = 1;
			if (i <= n % 1000)
				dp[3][i / 100][i / 10 % 10][i % 10][1] = 1;
		}
	}

	for (int i = 4; i < s.size(); ++i) {
		for (int j = 0; j < 10; ++j)
			for (int k = 0; k < 10; ++k)
				for (int l = 0; l < 10; ++l)
					for (int p = 0; p < 10; ++p) {
						int x = 1000 * s[i] + 100 * s[i - 1] + 10 * s[i - 2] + s[i - 3];
						int y = 1000 * j + 100 * k + 10 * l + p;

						if (check(y, 4)) {
							dp[i][j][k][l][0] += dp[i - 1][k][l][p][0];

							if (x >= y) {
								if (j < s[i])
									dp[i][j][k][l][1] += dp[i - 1][k][l][p][0];
								else
									dp[i][j][k][l][1] += dp[i - 1][k][l][p][1];
							}
						}
					}
	}

	ll ans = 0;
	for (int i = 0; i <= min(99ll, n); ++i)
		ans += check(i);

	for (int j = 1; j < 10; ++j)
		for (int k = 0; k < 10; ++k)
			for (int l = 0; l < 10; ++l)
				ans += dp[s.size() - 1][j][k][l][1];
	return ans;
}

signed main() {
	fast_io;

	ll a, b;
	cin >> a >> b;

	cout << f(b) - f(a - 1);
}

Compilation message (stderr)

numbers.cpp: In function 'bool check(long long int, long long int)':
numbers.cpp:33:18: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   33 |  while (s.size() < addlen)
      |         ~~~~~~~~~^~~~~~~~
numbers.cpp:36:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |  for (int i = 1; i < s.size(); ++i)
      |                  ~~^~~~~~~~~~
numbers.cpp:40:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |  for (int i = 2; i < s.size(); ++i)
      |                  ~~^~~~~~~~~~
numbers.cpp: In function 'long long int f(long long int)':
numbers.cpp:75:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |  for (int i = 4; i < s.size(); ++i) {
      |                  ~~^~~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 60 / 75