Submission #1238982

#	Time	Username	Problem	Language	Result	Execution time	Memory
1238982		trimkus	Collecting Stamps 3 (JOI20_ho_t3)	C++20	5 / 100	87 ms	107844 KiB

ho_t3

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int MAXN = 205;
ll dp[MAXN + 1][MAXN + 1][MAXN + 1][2];



int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    ll Lt;
    cin >> N >> Lt;
    vector<ll> x(N + 3);
    for (int i = 1; i <= N; ++i) {
    	cin >> x[i];
    }
    vector<ll> t(N + 3);
    for (int i = 1; i <= N; ++i) {
    	cin >> t[i];
    }
    for (int i = 0; i <= N + 2; ++i) {
    	for (int j = 0; j <= N + 2; ++j) {
    		for (int k = 0; k <= N + 2; ++k) {
    			for (int l = 0; l < 2; ++l) {
    				dp[i][j][k][l] = -1;
    			}
    		}
    	}
    }
    auto dist = [&](int L, int R, int side, int to) -> ll {
    	ll mn = 1e18;
    	if (side == 0) {
    		mn = min(abs(x[L] - x[to]), Lt - abs(x[L] - x[to]));
    	} else {
    		mn = min(abs(x[R] - x[to]), Lt - abs(x[R] - x[to]));
    	}
    	return mn;
    };
    auto dfs = [&](auto& dfs, int L, int R, int side, int take, ll T) -> ll {
    	if (L >= R) return 0;
    	if (dp[L][R][take][side] != -1) return dp[L][R][take][side];
    	ll res = 1e18;
    	if (L + 1 <= R && t[L + 1] >= T + dist(L, R, side, L + 1)) {
    		res = min(res, dfs(dfs, L + 1, R, 0, take + 1, T + dist(L, R, side, L + 1)));
    	} else if (L + 1 <= R) {
    		res = min(res, dfs(dfs, L + 1, R, 0, take, T + dist(L, R, side, L + 1)));
    	}
    	if (R - 1 >= L && t[R - 1] >= T + dist(L, R, side, R - 1)) {
    		res = min(res, dfs(dfs, L, R - 1, 1, take + 1, T + dist(L, R, side, R - 1)));
    	} else if (R - 1 >= L) {
    		res = min(res, dfs(dfs, L, R - 1, 1, take, T + dist(L, R, side, R - 1)));
    	}
		return dp[L][R][take][side] = res;
    };
	dfs(dfs, 0, N + 1, 0, 0, 0);
	dfs(dfs, 0, N + 1, 1, 0, 0);
	int res = -1;
	for (int i = 0; i <= N + 2; ++i) {
    	for (int j = 0; j <= N + 2; ++j) {
    		for (int k = 0; k <= N; ++k) {
    			for (int l = 0; l < 2; ++l) {
    				if (dp[i][j][k][l] == -1) continue;
    				if (dp[i][j][k][l] <= 1e18) {
    					res = max(res, k);
    				}
    			}
    		}
    	}
    }
    cout << res << "\n";
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 75