Submission #1332947

#	Time	Username	Problem	Language	Result	Execution time	Memory
1332947		retarde	Collecting Stamps 3 (JOI20_ho_t3)	C++20	100 / 100	617 ms	1041712 KiB

ho_t3

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

#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define int long long
#define all(x) (x).begin(), (x).end()

typedef long double ld;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<vector<int>> vvi;
typedef vector<vector<bool>> vvb;
typedef vector<vector<ll>> vvll;
typedef vector<string> vs;
typedef vector<vector<string>> vvs;
typedef vector<char> vc;
typedef vector<vector<char>> vvc;
typedef map<int, int> mii;
typedef unordered_map<int, int> umii;

const int mod = 1e9 + 7;
const int inf = INTMAX_MAX;
const bool tc = false;

const int mxn = 405;
int dp[mxn][mxn][mxn][2]; // dp[i][j][k][l] = minimum time for extending ith to jth picking k and on side l 
pii a[mxn]; int tim[mxn][mxn];
int n, l;

void pre() {
    for (int i = 0; i < mxn; i++) {
        for (int j = 0; j < mxn; j++) {
            for (int k = 0; k < mxn; k++) {
                dp[i][j][k][0] = 1e18;
                dp[i][j][k][1] = 1e18;
            }
        }
    }
}

void pre2() {
    for (int i = 0; i <= 2*n; i++) {
        tim[i][i] = 0;
        for (int j = i + 1; j <= 2*n; j++) {
            tim[i][j] = tim[i][j - 1] + (a[j].fi - a[j - 1].fi);
        }
    }
}   

inline void solve() {
    cin >> n >> l;
    vector<pii> st(n); for (int i = 0; i < n; i++) cin >> st[i].fi;
    for (int i = 0; i < n; i++) cin >> st[i].se;
    for (int i = 0; i < n; i++) a[i] = {st[i].fi - l, st[i].se};
    a[n] = {0, 0};
    for (int i = n + 1; i < n + 1 + n; i++) a[i] = st[i - (n + 1)];
    pre2();

    // indices from 0 to 2*n, n is anchor
    dp[n][n][1][0] = dp[n][n][1][1] = 0;
    dp[n][n][0][0] = dp[n][n][0][1] = 0;
    for (int l = n; l >= 0; l--) {
        for (int r = n; r <= 2*n; r++) {
            if (l == n && r == n) continue;
            if (l != n) {
                // assume i came from l + 1, r ie i moved l--
                for (int k = 0; k < mxn; k++) {
                    if (dp[l + 1][r][k][0] == 1e18) continue;
                    int tottime = dp[l + 1][r][k][0] + (a[l + 1].fi - a[l].fi);
                    dp[l][r][k][0] = min(dp[l][r][k][0], tottime);
                    if (k != mxn - 1 && tottime <= a[l].se) dp[l][r][k + 1][0] = min(dp[l][r][k + 1][0], tottime);
                }

                // assume i came from r
                for (int k = 0; k < mxn; k++) {
                    if (dp[l + 1][r][k][1] == 1e18) continue;
                    int tottime = dp[l + 1][r][k][1] + tim[l][r];
                    dp[l][r][k][0] = min(dp[l][r][k][0], tottime);
                    if (k != mxn - 1 && tottime <= a[l].se) dp[l][r][k + 1][0] = min(dp[l][r][k + 1][0], tottime);
                }
            }
            if (r != n) {
                // assume i came from r - 1
                for (int k = 0; k < mxn; k++) {
                    if (dp[l][r - 1][k][1] == 1e18) continue;
                    int tottime = dp[l][r - 1][k][1] + (a[r].fi - a[r - 1].fi);
                    dp[l][r][k][1] = min(dp[l][r][k][1], tottime);
                    if (k != mxn - 1 && tottime <= a[r].se) dp[l][r][k + 1][1] = min(dp[l][r][k + 1][1], tottime);
                }

                // assume i came from r
                for (int k = 0; k < mxn; k++) {
                    if (dp[l][r - 1][k][0] == 1e18) continue;
                    int tottime = dp[l][r - 1][k][0] + tim[l][r];
                    dp[l][r][k][1] = min(dp[l][r][k][1], tottime);
                    if (k != mxn - 1 && tottime <= a[r].se) dp[l][r][k + 1][1] = min(dp[l][r][k + 1][1], tottime);
                }
            }
        }
    }

    // for (int l = n; l >= 0; l--) {
    //     for (int k = 0; k <= 2 * n; k++) {
    //         for (int t = 0; t < 2; t++) {
    //             cout << "0 to " << l-n << " picking up " << k << " facing " << (t ? "right" : "left") << " is " << dp[l][n][k][t] << "\n";
    //         }
    //     }
    // }
    
    int ans = 0;
    for (int i = 0; i <= 2*n; i++) {
        for (int j = 0; j <= 2*n; j++) {
            for (int k = 0; k <= 2*n; k++) {
                for (int l = 0; l < 2; l++) {
                    if (dp[i][j][k][l] == 1e18) continue;
                    if (abs(i - j) > n) continue;
                    ans = max(ans, k);
                }
            }
        }
    }
    cout << ans - 1 << '\n';
}

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

signed main() {
    ios::sync_with_stdio(false);
    cout.tie(0);
    cin.tie(0);
    pre();

    int t = 1;
    if (tc) {
        cin >> t;
    }

    while (t--) {
        solve();
    }
}

Compilation message (stderr)

ho_t3.cpp: In function 'void setIO(std::string)':
ho_t3.cpp:134:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  134 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ho_t3.cpp:135:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  135 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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