Submission #982782

#	Time	Username	Problem	Language	Result	Execution time	Memory
982782		LOLOLO	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	123 ms	145640 KiB

ho_t3

#include <bits/stdc++.h>
#define ll long long
using namespace std;
 
#define           f     first
#define           s     second
#define           pb    push_back
#define           ep    emplace
#define           eb    emplace_back
#define           lb    lower_bound
#define           ub    upper_bound
#define       all(x)    x.begin(), x.end()
#define      rall(x)    x.rbegin(), x.rend()
#define   uniquev(v)    sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define     mem(f,x)    memset(f , x , sizeof(f))
#define        sz(x)    (int)(x).size()
#define  __lcm(a, b)    (1ll * ((a) / __gcd((a), (b))) * (b))
#define          mxx    *max_element
#define          mnn    *min_element
#define    cntbit(x)    __builtin_popcountll(x)
#define       len(x)    (int)(x.length())
 
const int N = 210;

ll f[N][N][N][2];
ll x[N], t[N];

void minimize(ll &a, ll b) {
    if (a > b)
        a = b;
}

ll n, l;
ll dis(ll a, ll b) {
    return min(abs(a - b), l - abs(a - b));
}

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

    mem(f, 0x3f);

    cin >> n >> l;

    for (int i = 0; i <= n + 1; i++) {
        for (int j = 0; j <= n + 1; j++) {
            for (int k = 0; k <= n + 1; k++) {
                f[i][j][k][0] = f[i][j][k][1] = 1e15;
            }
        }
    }

    for (int i = 1; i <= n; i++)
        cin >> x[i];

    for (int i = 1; i <= n; i++) 
        cin >> t[i];

    x[0] = 0;
    x[n + 1] = l;
    t[0] = -1;
    t[n + 1] = -1;
    f[0][0][n + 1][0] = 0;
    f[0][0][n + 1][1] = 0;

    int ans = 0;
    for (int c = 0; c <= n; c++) {
        for (int i = 0; i <= n + 1; i++) {
            for (int j = n + 1; j > i; j--) {
                if (i) {
                    if (c) {
                        ll ti = min(f[c - 1][i - 1][j][0] + dis(x[i - 1], x[i]), f[c - 1][i - 1][j][1] + dis(x[j], x[i])); 
                        if (ti <= t[i])
                            minimize(f[c][i][j][0], ti); 
                    }

                    minimize(f[c][i][j][0], min(f[c][i - 1][j][0] + dis(x[i - 1], x[i]), f[c][i - 1][j][1] + dis(x[j], x[i])));
                } 

                if (j != n + 1) {
                    if (c) {
                        ll ti = min(f[c - 1][i][j + 1][1] + dis(x[j + 1], x[j]), f[c - 1][i][j + 1][0] + dis(x[j], x[i])); 
                        if (ti <= t[j])
                            minimize(f[c][i][j][1], ti); 
                    }

                    minimize(f[c][i][j][1], min(f[c][i][j + 1][1] + dis(x[j + 1], x[j]), f[c][i][j + 1][0] + dis(x[j], x[i])));
                }

                if (min(f[c][i][i][0], f[c][i][j][1]) < 1e14)
                    ans = max(ans, c);
            }
        }
    }

    cout << ans << '\n';
    return 0;
}  

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