Submission #1239006

#	Time	Username	Problem	Language	Result	Execution time	Memory
1239006		trimkus	Collecting Stamps 3 (JOI20_ho_t3)	C++20	100 / 100	79 ms	133960 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];


void chmin(ll& x, ll y) {
	x = min(x, y);
}
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];
    }
    x[0] = 0;
    x[N + 1] = Lt;
    vector<ll> t(N + 3, -1);
    for (int i = 1; i <= N; ++i) {
    	cin >> t[i];
    }
    const ll INF = 1e18;
    t[0] = -INF;
    t[N + 1] = -INF;
    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] = INF;
    			}
    		}
    	}
    }
    dp[0][N + 1][0][0] = dp[0][N + 1][0][1] = 0;
    auto dist = [&](ll X, ll Y) -> ll {
    	// if (min(abs(X - Y), Lt - abs(X - Y)) == 0) {
    		// cout << X << " " << Y << "\n";
    	// }
    	// assert(min(abs(X - Y), Lt - abs(X - Y)) > 0);
    	return min(abs(X - Y), Lt - abs(X - Y));
    };
    for (int l = 0; l < N; ++l) {
    	for (int r = N + 1; r - 1 > l; --r) {
    		for (int k = 0; k <= N; ++k) {
    			ll tim = min(dp[l][r][k][0] + dist(x[l + 1], x[l]),
    				dp[l][r][k][1] + dist(x[l + 1], x[r]));
    			if (tim <= t[l + 1]) {
    				chmin(dp[l + 1][r][k + 1][0],
    					tim);
    			} else {
    				chmin(dp[l + 1][r][k][0],
    					tim);
    			}
    			tim = min(dp[l][r][k][0] + dist(x[l], x[r - 1]),
    				dp[l][r][k][1] + dist(x[r], x[r - 1]));
    			if (tim <= t[r - 1]) {
    				chmin(dp[l][r - 1][k + 1][1],
    					tim);
    			} else {
    				chmin(dp[l][r - 1][k][1],
    					tim);
    			}
    		}
    	}
    }
    int res = 0;
    for (int i = 0; i <= N + 1; ++i) {
    	for (int j = 0; j <= N + 1; ++j) {
    		for (int k = 0; k <= N; ++k) {
    			for (int z = 0; z < 2; ++z) {
    				if (dp[i][j][k][z] >= INF) continue;
    				res = max(res, k);
    			}
    		}
    	}
    }
    cout << res << "\n";
    
}

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