Submission #285576

#	Time	Username	Problem	Language	Result	Execution time	Memory
285576		kaplanbar	Collecting Stamps 3 (JOI20_ho_t3)	C++14	100 / 100	182 ms	135416 KiB

ho_t3

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int N = 205;
int n, m;
ll x[2*N], t[2*N], dp[N][N][N][2];
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m;
    for(int i = 0; i < n; i++) {
        cin >> x[i];
    }
    for(int i = 0; i < n; i++) {
        cin >> t[i];
    }
    auto dist = [&](int now, int next) {
        int d = min(m - now, now);
        d += min(next, m - next);
        return min(abs(now - next), d);
    };
    x[n] = 0;
    t[n] = 1e9;
    for(int i = 1; i <= n; i++) {
        x[n + i] = x[i - 1];
        t[n + i] = t[i - 1];
    }
    for(int i = 0; i < N; i++) for(int j = 0; j < N; j++) for(int k = 0; k < N; k++) dp[i][j][k][0] = dp[i][j][k][1] = 1e18;
    dp[0][0][0][0] = dp[0][0][0][1] = 0;
    for(int l = 0; l <= n; l++) {
        for(int r = 0; l + r < n; r++) {
            if(l == n || r == n) continue;
            for(int cnt = 0; cnt <= l + r; cnt++) {
                for(int dir = 0; dir <= 1; dir++) {  
                    if(dp[l][r][cnt][dir] == 1e18) continue;
                    int now = dir ? x[n + r] : x[n - l];
                    int next = x[n + r + 1];
                    ll tim = t[n + r + 1];
                    ll tum = dp[l][r][cnt][dir] + dist(now, next);
                    dp[l][r + 1][cnt + (tum <= tim)][1] = min(dp[l][r + 1][cnt + (tum <= tim)][1], tum);
                    
                    next = x[n - l - 1];
                    tim = t[n - l - 1];
                    tum = dp[l][r][cnt][dir] + dist(now, next);
                    dp[l + 1][r][cnt + (tum <= tim)][0] = min(dp[l + 1][r][cnt + (tum <= tim)][0], tum);
                }
            }
        }
    }
    int ans = 0;
    for(int l = 0; l <= n; l++) for(int r = 0; r <= n; r++) for(int cnt = 0; cnt <= l + r; cnt++) {
        if(dp[l][r][cnt][0] < 1e18 || dp[l][r][cnt][1] < 1e18) ans = max(ans, cnt);
    }
    cout << ans;
    return 0;
}

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