Submission #689402

#	Time	Username	Problem	Language	Result	Execution time	Memory
689402		stevancv	Collecting Stamps 3 (JOI20_ho_t3)	C++14	100 / 100	97 ms	129388 KiB

ho_t3

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 200 + 2;
const ll linf = 1e18;
ll dp[N][N][N][2];
int a[N], b[N];
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, L;
    cin >> n >> L;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= n; i++) cin >> b[i];
    a[n + 1] = L;
    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] = linf;
            }
        }
    }
    dp[0][0][0][0] = dp[0][0][0][1] = 0;
    for (int i = 0; i <= n; i++) {
        for (int j = 0; j <= n - i; j++) {
            for (int k = 0; k <= i + j; k++) {
                if (i > 0) {
                    smin(dp[i][j][k][0], dp[i - 1][j][k][1] + L - a[n - j + 1] + a[i]);
                    if (k > 0 && dp[i - 1][j][k - 1][1] + L - a[n - j + 1] + a[i] <= b[i])
                        smin(dp[i][j][k][0], dp[i - 1][j][k - 1][1] + L - a[n - j + 1] + a[i]);
                    smin(dp[i][j][k][0], dp[i - 1][j][k][0] + a[i] - a[i - 1]);
                    if (k > 0 && dp[i - 1][j][k - 1][0] + a[i] - a[i - 1] <= b[i])
                        smin(dp[i][j][k][0], dp[i - 1][j][k - 1][0] + a[i] - a[i - 1]);
                }
                if (j > 0) {
                    smin(dp[i][j][k][1], dp[i][j - 1][k][0] + L - a[n - j + 1] + a[i]);
                    if (k > 0 && dp[i][j - 1][k - 1][0] + L - a[n - j + 1] + a[i] <= b[n - j + 1])
                        smin(dp[i][j][k][1], dp[i][j - 1][k - 1][0] + L - a[n - j + 1] + a[i]);
                    smin(dp[i][j][k][1], dp[i][j - 1][k][1] - a[n - j + 1] + a[n - j + 2]);
                    if (k > 0 && dp[i][j - 1][k - 1][1] - a[n - j + 1] + a[n - j + 2] <= b[n - j + 1])
                        smin(dp[i][j][k][1], dp[i][j - 1][k - 1][1] - a[n - j + 1] + a[n - j + 2]);
                }
            }
        }
    }
    int ans = 0;
    for (int i = 0; i <= n; i++) {
        for (int j = 0; j <= n - i; j++) {
            for (int k = 0; k <= i + j; k++) {
                if (dp[i][j][k][0] != linf) smax(ans, k);
                if (dp[i][j][k][1] != linf) smax(ans, k);
            }
        }
    }
    cout << ans << en;
    return 0;
}

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