Submission #577717

#	Time	Username	Problem	Language	Result	Execution time	Memory
577717		Jomnoi	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	254 ms	132868 KiB

ho_t3

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

const int MAX_N = 205;
const long long llINF = 1e18 + 7;

int X[MAX_N], T[MAX_N];
long long dp1[MAX_N][MAX_N][MAX_N], dp2[MAX_N][MAX_N][MAX_N];

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    
    int N, L;
    cin >> N >> L;
    
    for(int i = 1; i <= N; i++) {
        cin >> X[i];
    }
    for(int i = 1; i <= N; i++) {
        cin >> T[i];
    }
    X[N + 1] = L;

    for(int k = 0; k <= N; k++) {
        for(int i = 0; i <= N + 1; i++) {
            for(int j = 0; j <= N + 1; j++) {
                dp1[i][j][k] = llINF;
                dp2[i][j][k] = llINF;
            }
        }
    }

    int ans = 0;
    dp1[0][N + 1][0] = dp2[0][N + 1][0] = 0;
    for(int k = 0; k <= N; k++) {
        for(int i = 0; i <= N; i++) {
            for(int j = N + 1; j >= i + 1; j--) {
                if(i - 1 >= 0) {
                    if(k - 1 >= 0 and dp1[i - 1][j][k - 1] + X[i] - X[i - 1] <= T[i]) {
                        dp1[i][j][k] = min(dp1[i][j][k], dp1[i - 1][j][k - 1] + X[i] - X[i - 1]);
                    }
                    if(dp1[i - 1][j][k] + X[i] - X[i - 1] > T[i]) {
                        dp1[i][j][k] = min(dp1[i][j][k], dp1[i - 1][j][k] + X[i] - X[i - 1]);
                    }

                    if(k - 1 >= 0 and dp2[i - 1][j][k - 1] + (L - X[j]) + X[i] <= T[i]) {
                        dp1[i][j][k] = min(dp1[i][j][k], dp2[i - 1][j][k - 1] + (L - X[j]) + X[i]);
                    }
                    if(dp2[i - 1][j][k] + (L - X[j]) + X[i] > T[i]) {
                        dp1[i][j][k] = min(dp1[i][j][k], dp2[i - 1][j][k] + (L - X[j]) + X[i]);
                    }
                }

                if(j + 1 <= N + 1) {
                    if(k - 1 >= 0 and dp2[i][j + 1][k - 1] + X[j + 1] - X[j] <= T[j]) {
                        dp2[i][j][k] = min(dp2[i][j][k], dp2[i][j + 1][k - 1] + X[j + 1] - X[j]);
                    }
                    if(dp2[i][j + 1][k] + X[j + 1] - X[j] > T[j]) {
                        dp2[i][j][k] = min(dp2[i][j][k], dp2[i][j + 1][k] + X[j + 1] - X[j]);
                    }

                    if(k - 1 >= 0 and dp1[i][j + 1][k - 1] + (L - X[j]) + X[i] <= T[j]) {
                        dp2[i][j][k] = min(dp2[i][j][k], dp1[i][j + 1][k - 1] + (L - X[j]) + X[i]);
                    }
                    if(dp1[i][j + 1][k] + (L - X[j]) + X[i] > T[j]) {
                        dp2[i][j][k] = min(dp2[i][j][k], dp1[i][j + 1][k] + (L - X[j]) + X[i]);
                    }
                }

                if(dp1[i][j][k] != llINF or dp2[i][j][k] != llINF) {
                    ans = k;
                }
            }
        }
    }
    cout << ans;
    return 0;
}

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