Submission #285443

#	Time	Username	Problem	Language	Result	Execution time	Memory
285443		a14789654	Palindrome-Free Numbers (BOI13_numbers)	C++17	73.75 / 100	3 ms	2944 KiB

numbers

#include <bits/stdc++.h>

using namespace std;

long long f[20][2][2][20][10][10][2];
string a, b;
int n;

long long calc(int pos, bool ok1, bool ok2, int start, int prev, int prevPrev, bool check)
{
    if (pos == n + 1) return !check;
    if (f[pos][ok1][ok2][start][prev][prevPrev][check] != - 1) return f[pos][ok1][ok2][start][prev][prevPrev][check];
    int low = 0, high = 9;
    if (ok1) low = a[pos] - '0';
    if (ok2) high = b[pos] - '0';
    long long res = 0;
    for (int i = low; i <= high; ++i)
    {
        bool okI = ok1 && i == a[pos] - '0', okII = ok2 && i == b[pos] - '0';
        int first = (!start && i) ? pos : start;
        bool okIII = check;
        okIII |= (start && i == prev);
        okIII |= (pos - start + 1 > 2 && i == prevPrev);
        res += calc(pos + 1, okI, okII, first, i, prev, okIII);
    }
    return f[pos][ok1][ok2][start][prev][prevPrev][check] = res;
}

int main()
{
//    freopen("test.inp", "r", stdin);
//    freopen("test.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    cin >> a >> b;
    while (a.size() < b.size()) a = "0" + a;
    n = a.size();
    a = "p" + a, b = "p" + b;
    memset(f, - 1, sizeof(f));
    cout << calc(1, 1, 1, 0, 0, 0, 0);
    return 0;
}

• Subtask 1: 13.75 / 25
• Subtask 2: 60 / 75