Submission #813472

#	Time	Username	Problem	Language	Result	Execution time	Memory
813472		Blagoj	Palindrome-Free Numbers (BOI13_numbers)	C++17	100 / 100	1 ms	376 KiB

numbers

#include <bits/stdc++.h>

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

using namespace std;

#define endl '\n'
#define ll long long
#define all(x) x.begin(), x.end()

string goal;

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

ll calc(int pos, int beforeLast, int last, bool bigger, bool leading) {
	if (dp[pos][beforeLast][last][bigger][leading]) return dp[pos][beforeLast][last][bigger][leading];
	if (pos == goal.size()) return dp[pos][beforeLast][last][bigger][leading] = 1;
	ll ans = 0;
	if (pos == 0) {
		for (int i = 0; i <= min(9, goal[0] - '0'); i++) ans += calc(pos + 1, last, i == 0 ? 10 : i, i < goal[0] - '0', i == 0);
		return dp[pos][beforeLast][last][bigger][leading] = ans;
	}
	else if (leading) {
		for (int i = 0; i < 10; i++) ans += calc(pos + 1, last, i == 0 ? 10 : i, 1, (i == 0));
		return dp[pos][beforeLast][last][bigger][leading] = ans;
	}
	else {
		for (int i = 0; i < 10; i++) {
			if (last != i && beforeLast != i) {
				if (bigger) ans += calc(pos + 1, last, i, 1, 0);
				else if (i <= goal[pos] - '0') ans += calc(pos + 1, last, i, i < goal[pos] - '0', 0);
			}
		}
	}
	return dp[pos][beforeLast][last][bigger][leading] = ans;
}

ll solve(ll x) {
	memset(dp, 0, sizeof(dp));
	goal = to_string(x);
	return calc(0, 10, 10, 0, 0);
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	ll l, r;
	cin >> l >> r;
	cout << solve(r) - (l != 0 ? solve(l - 1) : 0);
}

Compilation message (stderr)

numbers.cpp: In function 'long long int calc(int, int, int, bool, bool)':
numbers.cpp:21:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  if (pos == goal.size()) return dp[pos][beforeLast][last][bigger][leading] = 1;
      |      ~~~~^~~~~~~~~~~~~~

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