Submission #647913

#	Time	Username	Problem	Language	Result	Execution time	Memory
647913		LeonaRaging	Collecting Stamps 3 (JOI20_ho_t3)	C++14	100 / 100	118 ms	135264 KiB

ho_t3

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

#define int long long
#define fi first
#define se second
#define ll long long
#define pb push_back
#define db(val) "[" #val " = " << (val) << "] "

const ll mod = 1e9 + 7;
const int maxn = 1e5 + 4;
const int N = 205;

int n, L, x[N], t[N], dp[N][N][N][2], INF;

void MIN(int &a, int b) {
    if (a > b) a = b;
}

int dist(int from, int to) {
    if (from > to) swap(from, to);
    return min(x[to] - x[from], L - (x[to] - x[from]));
}

signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    //freopen(".INP", "r", stdin);
    //freopen(".OUT", "w", stdout);
    cin >> n >> L;
    for (int i = 1; i <= n; i++)
        cin >> x[i];
    for (int i = 1; i <= n; i++)
        cin >> t[i];
    memset(dp, 63, sizeof dp);
    INF = dp[0][0][0][0];
    dp[0][n + 1][0][0] = 0;
    x[n + 1] = L;
    for (int sz = n + 1; sz > 1; sz--) {
        for (int i = 0; i <= n + 1 - sz; i++) {
            int j = i + sz;
            for (int k = 0; k <= n; k++) {
                int x;
                if (dp[i][j][k][0] != INF) {
                    x = dp[i][j][k][0] + dist(i, i + 1);
                    MIN(dp[i + 1][j][k + (x <= t[i + 1])][0], x);
                    x = dp[i][j][k][0] + dist(i, j - 1);
                    MIN(dp[i][j - 1][k + (x <= t[j - 1])][1], x);
                }
                if (dp[i][j][k][1] != INF) {
                    x = dp[i][j][k][1] + dist(j, i + 1);
                    MIN(dp[i + 1][j][k + (x <= t[i + 1])][0], x);
                    x = dp[i][j][k][1] + dist(j, j - 1);
                    MIN(dp[i][j - 1][k + (x <= t[j - 1])][1], x);
                }
            }   
        }
    }
    int ans = 0;
    for (int k = 0; k <= n; k++)
        for (int i = 0; i <= n; i++)
            if (dp[i][i + 1][k][0] != INF || dp[i][i + 1][k][1] != INF)
                ans = k;
    cout << ans;
}

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