Submission #1267353

#	Time	Username	Problem	Language	Result	Execution time	Memory
1267353		gay	Collecting Stamps 3 (JOI20_ho_t3)	C++20	15 / 100	1758 ms	1114112 KiB

ho_t3

#include <bits/stdc++.h>
#include <experimental/random>
#include <random>

using namespace std;
using ll = long long;
using ld = long double;

const ll INF = 1e18, MOD = 998244353;

void solve();

signed main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll q = 1;
    //cin >> q;
    while (q--) {
        solve();
    }
}

unordered_map<ll, ll> dp[401][401][2];

void solve() {
    ll n, all;
    cin >> n >> all;
    vector<ll> x(n);
    ll prev = 0;
    for (int i = 0; i < n; i++) {
        ll t;
        cin >> t;
        x[i] = t - prev;
        prev = t;
    }

    vector<ll> t(n);
    for (int i = 0; i < n; i++) {
        cin >> t[i];
    }

    vector<ll> a;
    for (int i = 0; i < n; i++) {
        a.push_back(t[i]);
    }
    a.push_back(INF);
    for (int i = 0; i < n; i++) {
        a.push_back(t[i]);
    }

    vector<ll> b;
    for (int i = 1; i < n; i++) {
        b.push_back(x[i]);
    }
    b.push_back(all - prev);
    for (int i = 0; i < n; i++) {
        b.push_back(x[i]);
    }

    vector<ll> pref = {0};
    for (auto i : b) {
        pref.push_back(pref.back() + i);
    }

    dp[n][n][0][0] = 0;
    ll ans = 0;

    for (int len = 1; len <= n + 1; len++) {
        for (int l = 0; l + len <= 2 * n + 1; l++) {
            ll r = l + len - 1;
            for (auto [time, cnt] : dp[l][r][0]) {
                ans = max(ans, cnt);
                if (len == n + 1) {
                    continue;
                }
                ll nw_time = time + b[l - 1];
                ll cost = cnt;
                if (nw_time <= a[l - 1]) {
                    cost++;
                }
                dp[l - 1][r][0][nw_time] = max(dp[l - 1][r][0][nw_time], cost);

                nw_time = time + pref[r + 1] - pref[l];
                cost = cnt;
                if (nw_time <= a[r + 1]) {
                    cost++;
                }
                dp[l][r + 1][1][nw_time] = max(dp[l][r + 1][1][nw_time], cost);
            }

            for (auto [time, cnt] : dp[l][r][1]) {
                ans = max(ans, cnt);
                if (len == n + 1) {
                    continue;
                }
                ll nw_time = time + pref[r] - pref[l - 1];
                ll cost = cnt;
                if (nw_time <= a[l - 1]) {
                    cost++;
                }
                dp[l - 1][r][0][nw_time] = max(dp[l - 1][r][0][nw_time], cost);

                nw_time = time + b[r];
                cost = cnt;
                if (nw_time <= a[r + 1]) {
                    cost++;
                }
                dp[l][r + 1][1][nw_time] = max(dp[l][r + 1][1][nw_time], cost);
            }
        }
    }

    cout << ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 75