Submission #630031

#	Time	Username	Problem	Language	Result	Execution time	Memory
630031		colossal_pepe	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	1025 ms	42308 KiB

ho_t3

#include <iostream>
#include <vector>
#include <queue>
#include <tuple>
using namespace std;

const int INF = (int)1e9 + 1;
const int N = 205;

int n, l, x[N], t[N], dp[N][N][N];

int dist(int x1, int x2) {
    if (x1 > x2) swap(x1, x2);
    return min(x2 - x1, l - x2 + x1);
}

int solve() {
    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] = -INF;
            }
        }
    }
    int ans = 0;
    priority_queue<tuple<int, int, int, int>> pq;
    dp[0][n + 1][0] = 0;
    pq.push({0, 0, n + 1, 0});
    while (not pq.empty()) {
        int d, i, j, c;
        tie(d, i, j, c) = pq.top();
        ans = max(ans, c);
        pq.pop();
        if (dp[i][j][c] != d or abs(i - j) == 1) continue;
        int cur = i, l = min(i, j), r = max(i, j);
        {
            // cur -> l + 1
            int d_nxt = min(INF, dist(x[cur], x[l + 1]) - d);
            int c_nxt = (d_nxt <= t[l + 1]) + c;
            if (dp[l + 1][r][c_nxt] < -d_nxt) {
                dp[l + 1][r][c_nxt] = -d_nxt;
                pq.push({-d_nxt, l + 1, r, c_nxt});
            }
        }
        {
            // cur -> r - 1
            int d_nxt = min(INF, dist(x[cur], x[r - 1]) - d);
            int c_nxt = (d_nxt <= t[r - 1]) + c;
            if (dp[r - 1][l][c_nxt] < -d_nxt) {
                dp[r - 1][l][c_nxt] = -d_nxt;
                pq.push({-d_nxt, r - 1, l, c_nxt});
            }
        }
    }
    return ans;
}

int main() {
    cin >> n >> l;
    x[0] = 0;
    for (int i = 1; i <= n; i++) {
        cin >> x[i];
    }
    for (int i = 1; i <= n; i++) {
        cin >> t[i];
    }
    cout << solve() << '\n';
    return 0;
}

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