Submission #1102887

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102887		Cam	Palindrome-Free Numbers (BOI13_numbers)	C++17	100 / 100	4 ms	1796 KiB

numbers

#include <bits/stdc++.h>
#define name "palinfree"
#define ll long long
#define db double
#define pb push_back
#define ii pair<int,int>
#define mp make_pair
#define fi first
#define se second
#define bit(x,i) (((x)>>(i))&1)
#define sz(s) (int)(s).size()
#define all(a) (a).begin(),(a).end()
#define rep(i,a,b) for(int i=(a), _b=(b); i<=_b; i++)
#define repd(i,a,b) for(int i=(a), _b=(b); i>=_b; i--)
#define _unique(x) (x).resize(unique(all(x)) - (x).begin())

using namespace std;

const int N = 1e5 + 3;

ll l, r;
ll f[25][2][25][13][13];
vector <int> digit;

ll Try (int i, bool isless, bool ok, int cnt, int pre1, int pre2, int s) {

    if (i == -1) {
        //if (ok) cout << s << "\n";
        return ok;
    }
    if (isless && f[i][ok][cnt][pre1][pre2] != -1) return f[i][ok][cnt][pre1][pre2];
    ll res = 0;
    int mx = (isless ? 9 : digit[i]);
    rep (j, 0, mx) {

        if (!ok && j == 0) res += Try (i - 1, isless || j < mx, 0, 0, pre2, j, s * 10 + j);
        else {

            if (cnt <= 1) {
                if (j != pre2) res += Try (i - 1, isless || j < mx, 1, cnt + 1, pre2, j, s * 10 + j);
            }
            else if (j != pre1 && j != pre2) res += Try (i - 1, isless || j < mx, 1, cnt + 1, pre2, j, s * 10 + j);
        }
    }
    if (isless) f[i][ok][cnt][pre1][pre2] = res;
    return res;
}
ll sol (ll x) {

    digit.clear();
    while (x > 0) digit.pb (x % 10), x /= 10;
    return Try (sz (digit) - 1, 0, 0, 0, 0, 0, 0);
}

void solve (void) {

    cin >> l >> r;
    bool ok = 0;
    if (l > r) swap (l, r), ok = 1;
    rep (i, 0, 20) rep (ok, 0, 1) rep (cnt, 0, 20) rep (pre1, 0, 9) rep (pre2, 0, 9) f[i][ok][cnt][pre1][pre2] = -1;
    ll res = sol (r) - sol (l - 1);
    if (l == 0) res ++;
    if (ok) res *= -1;
    cout << res;
}

signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    //freopen(name".inp","r",stdin);
    //freopen(name".out","w",stdout);

    solve();
    return 0;
}

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