Submission #346691

#	Time	Username	Problem	Language	Result	Execution time	Memory
346691		illequiprogrammat	Palindrome-Free Numbers (BOI13_numbers)	C++14	13.75 / 100	1 ms	640 KiB

numbers

#include <iostream>
#include <vector>
using namespace std;

typedef long long ll;

struct SOLUTION {
    bool vis[30][11][11][2];
    // memo[index][penultimate][end_digit][tight];
    ll memo[30][11][11][2];

    vector<int> digits;

    ll dp(int index, int penultimate, int end, bool tight) {
        if (index == digits.size()) return 1;
        if (vis[index][penultimate][end][tight])
            return memo[index][penultimate][end][tight];
        ll res = 0;
        
        int start = 0;
        int max_next = 9;
        if (tight) max_next = digits[digits.size() - index - 1];
        if (index == 0) start = 1;

        for (int i = start; i <= max_next; i++) {
            if (i != penultimate && i != end) {
                res += dp(index + 1, end, i, tight && i == max_next);
            }
        }


        vis[index][penultimate][end][tight] = true;
        memo[index][penultimate][end][tight] = res;
        return res;
    }

    void get_digits(ll n) {
        while (n != 0) {
            digits.push_back(n%10);
            n /= 10;
        }
    }

    bool is_palindrome() {
        bool res = false;
        for (int i = 0; i < digits.size()-1; i++) {
            if (digits[i] == digits[i+1]) res = true;
        }
        for (int i = 0; i < digits.size()-2; i++) {
            if (digits[i] == digits[i+2]) res = true;
        }
        return res;
    }

};

int main() {
    int a, b;
    SOLUTION l_bound;
    SOLUTION u_bound;
    cin >> a >> b;
    l_bound.get_digits(a);
    int lres = l_bound.dp(0, 0, 11, true);
    u_bound.get_digits(b);
    int ures = u_bound.dp(0, 0, 11, true);
    if (l_bound.is_palindrome()) {
        cout << ures - lres << endl;
    } else {
        cout << ures - lres + 1 << endl;
    }
}

Compilation message (stderr)

numbers.cpp: In member function 'll SOLUTION::dp(int, int, int, bool)':
numbers.cpp:15:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |         if (index == digits.size()) return 1;
      |             ~~~~~~^~~~~~~~~~~~~~~~
numbers.cpp: In member function 'bool SOLUTION::is_palindrome()':
numbers.cpp:46:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |         for (int i = 0; i < digits.size()-1; i++) {
      |                         ~~^~~~~~~~~~~~~~~~~
numbers.cpp:49:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |         for (int i = 0; i < digits.size()-2; i++) {
      |                         ~~^~~~~~~~~~~~~~~~~

• Subtask 1: 8.75 / 25
• Subtask 2: 5 / 75