Submission #876430

#	Time	Username	Problem	Language	Result	Execution time	Memory
876430		ArashJafariyan	Semiexpress (JOI17_semiexpress)	C++17	100 / 100	373 ms	55512 KiB

semiexpress

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

#define ll long long 
#define pb push_back

const int M = 3e3 + 4;

int n, m, k, a, b, c, s[M];
ll t, mx[M][M], dp[M][M];

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> m >> k;
    cin >> a >> b >> c;
    cin >> t;
    for (int i = 0; i < m; ++i) {
        cin >> s[i];
        --s[i];
    }
    k -= m; // k: number of semi-express stations we need to add
    s[m] = n;

    // mx[i][j]: maximum distance to travel from station s[i] if we use exactly j semi-express station
    // dp[i][j]: maximum answer if we use i stations from s and j semi-express station

    for (int i = 0; i < m; ++i) {
        ll preCost = 1ll * s[i] * b; 
        if (preCost > t)
            break;

        mx[i][0] = (t - preCost) / a;
        mx[i][0] = min(mx[i][0], 0ll + s[i + 1] - s[i] - 1);
        for (int j = 1; j <= k; ++j) {
            if (mx[i][j - 1] == s[i + 1] - s[i] - 1) {
                mx[i][j] = mx[i][j - 1];
                break;
            }
            
            preCost = 1ll * s[i] * b + 1ll * c * (mx[i][j - 1] + 1);
            if (preCost > t) {
                mx[i][j] = mx[i][j - 1];
                break;
            }
            ll canTravel = (t - preCost) / a;

            mx[i][j] = mx[i][j - 1] + 1 + canTravel;
            mx[i][j] = min(mx[i][j], 0ll + s[i + 1] - s[i] - 1);
        }

        if (i == 0) 
            for (int j = 0; j <= k; ++j)
                dp[i][j] = mx[i][j];
        else 
            for (int j = 0; j <= k; ++j) 
                for (int l = 0; l <= j; ++l)
                    dp[i][j] = max(dp[i][j], dp[i - 1][j - l] + mx[i][l] + 1);
    }

    ll ans = 0;
    for (int i = 0; i < m; ++i)
        for (int j = 0; j <= k; ++j)
            ans = max(ans, dp[i][j]);
    cout << ans;

    return 0;
}

• Subtask 1: 18 / 18
• Subtask 2: 30 / 30
• Subtask 3: 52 / 52