Submission #256354

#	Time	Username	Problem	Language	Result	Execution time	Memory
256354		vioalbert	Collecting Stamps 3 (JOI20_ho_t3)	C++14	100 / 100	132 ms	129404 KiB

ho_t3

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

const ll N = 205, INF = 1e18;
ll n, l;
ll cl[N], ccl[N], t[N];

void read() {
	cin >> n >> l;
	cl[0] = 0, cl[n+1] = l;
	ccl[0] = l, cl[n+1] = 0;
	for(int i = 1; i <= n; i++) {
		cin >> cl[i];
		ccl[i] = l - cl[i];
	}
	for(int i = 1; i <= n; i++)
		cin >> t[i];
}

struct state {
	int l, r, cnt, dir;
	state(int _l, int _r, int _cnt, int _dir) : l(_l), r(_r), cnt(_cnt), dir(_dir) {}
	bool operator<(const state& ot) const {
		return cnt < ot.cnt;
	}
};

void solve() {
	priority_queue<pair<ll, state>, vector<pair<ll, state>>, greater<pair<ll, state>>> pq;
	ll dp[n+2][n+2][n+2][2];
	for(int l = 0; l <= n+1; l++) {
		for(int r = 0; r <= n+1; r++) {
			for(int cnt = 0; cnt <= n; cnt++)
				dp[l][r][cnt][0] = dp[l][r][cnt][1] = INF;
		}
	}
	dp[0][n+1][0][0] = 0;

	for(int l = 0; l <= n+1; l++) {
		for(int r = n+1; r > l; r--) {
			for(int cnt = 0; cnt <= n; cnt++) {
				// cerr << l << ' ' << r << ' ' << cnt << '\n';
				ll dur;
				if(dp[l][r][cnt][0] < INF) {
					dur = dp[l][r][cnt][0] + cl[l + 1] - cl[l];
					dp[l + 1][r][cnt + (dur <= t[l + 1])][0] = min(dp[l + 1][r][cnt + (dur <= t[l + 1])][0], dur);
					dur = dp[l][r][cnt][0] + cl[l] + ccl[r - 1];
					dp[l][r - 1][cnt + (dur <= t[r - 1])][1] = min(dp[l][r - 1][cnt + (dur <= t[r - 1])][1], dur);
				}
				if(dp[l][r][cnt][1] < INF) {
					dur = dp[l][r][cnt][1] + ccl[r - 1] - ccl[r];
					dp[l][r - 1][cnt + (dur <= t[r - 1])][1] = min(dp[l][r - 1][cnt + (dur <= t[r - 1])][1], dur);
					dur = dp[l][r][cnt][1] + ccl[r] + cl[l + 1];
					dp[l + 1][r][cnt + (dur <= t[l + 1])][0] = min(dp[l + 1][r][cnt + (dur <= t[l + 1])][0], dur);
				}
			}
		}
	}

	ll ans = 0;
	for(int l = 0; l <= n; l++) {
		for(int r = l+1; r <= n+1; r++) {
			for(int cnt = 0; cnt <= n; cnt++) {
				if(min(dp[l][r][cnt][0], dp[l][r][cnt][1]) < INF)
					ans = max(ans, (ll)cnt);
			}
		}
	}

	cout << ans << '\n';
}

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	read();
	solve();
	return 0;
}

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