Submission #1264757

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264757		wedonttalkanymore	Collecting Stamps 3 (JOI20_ho_t3)	C++20	100 / 100	81 ms	130888 KiB

ho_t3

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

#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll N = 200 + 5, inf = 1e12, mod = 1e9 + 7, block = 320, lim = 16;

int n, L;
int x[N], t[N], x1[N], t1[N];
int dp[N][N][2][N];

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(".inp", "r")) {
        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++) x1[i] = L - x[n - i + 1];
    for (int i = 1; i <= n; i++) cin >> t[i];
    for (int i = 1; i <= n; i++) t1[i] = t[n - i + 1];
    x[0] = x1[0] = 0;
    t[0] = t1[0] = -1;
    for (int i = 0; i <= n; ++i)
        for (int j = 0; j <= n; ++j)
            for (int p = 0; p < 2; ++p)
                for (int c = 0; c <= n; ++c)
                    dp[i][j][p][c] = inf;
    dp[0][0][0][0] = dp[0][0][1][0] = 0;
    for (int sum = 0; sum <= n; sum++) {
        for (int l = 0; l <= sum; l++) {
            int r = sum - l;
            if (l > n || r > n) continue;
            for (int pos = 0; pos < 2; pos++) {
                for (int c = 0; c <= n; c++) {
                    int cur = dp[l][r][pos][c];
                    if (cur >= inf) continue;
                    if (pos == 0) {
                        int nxtL = l + 1, nxtR = r + 1;
                        if (nxtL <= n) {
                            int dist = cur + x1[nxtL] - x1[l];
                            int nxtC = c + (dist <= t1[nxtL] ? 1 : 0);
                            dp[nxtL][r][pos][nxtC] = min(dp[nxtL][r][pos][nxtC], dist);
                        }
                        if (nxtR <= n) {
                            int dist = cur + x[nxtR] + x1[l];
                            int nxtC = c + (dist <= t[nxtR] ? 1 : 0);
                            dp[l][nxtR][1][nxtC] = min(dp[l][nxtR][1][nxtC], dist);
                        }
                    }
                    else if (pos == 1) {
                        int nxtL = l + 1, nxtR = r + 1;
                        if (nxtL <= n) {
                            int dist = cur + x1[nxtL] + x[r];
                            int nxtC = c + (dist <= t1[nxtL] ? 1 : 0);
                            dp[nxtL][r][0][nxtC] = min(dp[nxtL][r][0][nxtC], dist);
                        }
                        if (nxtR <= n) {
                            int dist = cur + x[nxtR] - x[r];
                            int nxtC = c + (dist <= t[nxtR] ? 1 : 0);
                            dp[l][nxtR][pos][nxtC] = min(dp[l][nxtR][pos][nxtC], dist);
                        }
                    }
                }
            }
        }
    }
    int ans = 0;
    for (int sum = 1; sum <= n; sum++) {
        for (int l = 0; l <= sum; l++) {
            int r = sum - l;
            if (l > n || r > n) continue;
            for (int pos = 0; pos < 2; pos++) {
                for (int c = 0; c <= n; c++) {
                    if (dp[l][r][pos][c] < inf) ans = max(ans, c);
                }
            }
        }
    }
    cout << ans;
    return 0;
}

Compilation message (stderr)

ho_t3.cpp: In function 'int main()':
ho_t3.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
ho_t3.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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