Submission #786777

#	Time	Username	Problem	Language	Result	Execution time	Memory
786777		serifefedartar	Palindrome-Free Numbers (BOI13_numbers)	C++17	72.50 / 100	1 ms	340 KiB

numbers

#include <bits/stdc++.h>
using namespace std;

#define fast ios::sync_with_stdio(0);cin.tie(0);
typedef long long ll;
#define f first
#define s second
#define MAXN 100005
#define int long long

ll count(string x) {
    int len = x.length();

    vector<vector<vector<int>>> dp(11, vector<vector<int>>(11, vector<int>(2, 0)));
    dp[10][10][0] = 1;
    for (int i = 0; i < len; i++) {
        vector<vector<vector<int>>> new_dp(11, vector<vector<int>>(11, vector<int>(2, 0)));
        for (auto smaller : {false, true}) {
            for (int second_last = 0; second_last <= 10; second_last++) {
                for (int last_digit = 0; last_digit <= 10; last_digit++) {
                    for (int digit = 0; digit < 10; digit++) {
                        if (!smaller && digit > x[i]-'0')
                            break;
                        if (digit == last_digit || digit == second_last)
                            continue;
                        new_dp[digit][last_digit][smaller || digit < x[i]-'0'] += dp[last_digit][second_last][smaller];
                    }
                }
            }
        }
        dp = new_dp;
    }
    
    ll ans = 0;
    for (int second_last = 0; second_last < 10; second_last++)
        for (int last_digit = 0; last_digit < 10; last_digit++)
            ans += dp[last_digit][second_last][0] + dp[last_digit][second_last][1];
    return ans;
}

signed main() {
    fast
    ll a, b;
    cin >> a >> b;
    string strA = to_string(a-1), strB = to_string(b);
    ll ans = count(strB) - count(strA);
    cout << ans << endl;
}

• Subtask 1: 12.5 / 25
• Subtask 2: 60 / 75