Submission #1124278

#	Time	Username	Problem	Language	Result	Execution time	Memory
1124278		gdragon	Collecting Stamps 3 (JOI20_ho_t3)	C++20	100 / 100	126 ms	135312 KiB

ho_t3

#include <bits/stdc++.h>
using namespace std;
#define TASK "long"
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define GETBIT(mask, i) ((mask) >> (i) & 1)
#define MASK(i) ((1LL) << (i))
#define SZ(x) ((int)(x).size())
#define mp make_pair
#define CNTBIT(mask) __builtin_popcount(mask)
template<class X, class Y> bool maximize(X &x, Y y){ if (x < y) {x = y; return true;} return false;};
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y) {x = y; return true;} return false;};
typedef pair<int, int> ii;
const int N = 200 + 5;
const int inf = 1e9 + 7;
const long long INF = (long long)1e18 + 7;
const int mod = 1e9 + 7;
void add(int &x, int y) {x += y; if (x >= mod) x -= mod;}
void sub(int &x, int y) {x -= y; if (x < 0) x += mod;}
int mul(int x, int y) {return 1LL * x * y % mod;}
// -----------------------------------------//
int n, L;
int x[N], timer[N];
void read() {
    cin >> n >> L;
    for(int i = 1; i <= n; i++) cin >> x[i];
    for(int i = 1; i <= n; i++) cin >> timer[i];
}
long long dp[N][N][N][2];
void solve() {
    x[n + 1] = L;
    memset(dp, 0x3f, sizeof(dp));
    dp[0][n + 1][0][0] = 0;
    dp[0][n + 1][0][1] = 0;
    for(int l = 0; l < n; l++) {
        for(int r = n + 1; r >= l; r--) {
            for(int i = 0; i <= n; i++) {
                if (dp[l][r][i][0] < INF) {
                    if (l + 1 < r) minimize(dp[l + 1][r][i][0], dp[l][r][i][0] + x[l + 1] - x[l]);
                    if (l + 1 < r && dp[l][r][i][0] + x[l + 1] - x[l] <= timer[l + 1]) {
                        minimize(dp[l + 1][r][i + 1][0], dp[l][r][i][0] + x[l + 1] - x[l]);
                    }
                    if (l < r - 1) minimize(dp[l][r - 1][i][1], dp[l][r][i][0] + x[l] + L - x[r - 1]);
                    if (l < r - 1 && dp[l][r][i][0] + x[l] + L - x[r - 1] <= timer[r - 1]) {
                        minimize(dp[l][r - 1][i + 1][1], dp[l][r][i][0] + x[l] + L - x[r - 1]);
                    }
                }
                if (dp[l][r][i][1] < INF) {
                    if (l < r - 1) minimize(dp[l][r - 1][i][1], dp[l][r][i][1] + x[r] - x[r - 1]);
                    if (l < r - 1 && dp[l][r][i][1] + x[r] - x[r - 1] <= timer[r - 1]) {
                        minimize(dp[l][r - 1][i + 1][1], dp[l][r][i][1] + x[r] - x[r - 1]);
                    }
                    if (l + 1 < r) minimize(dp[l + 1][r][i][0], dp[l][r][i][1] + L - x[r] + x[l + 1]);
                    if (l + 1 < r && dp[l][r][i][1] + L - x[r] + x[l + 1] <= timer[l + 1]) {
                        minimize(dp[l + 1][r][i + 1][0], dp[l][r][i][1] + L - x[r] + x[l + 1]);
                    }
                }
            }
        }
    }
    int ans = 0;
    for(int l = 0; l <= n; l++) {
        for(int r = n + 1; r >= l; r--) {
            for(int i = 0; i <= n; i++) {
                if (dp[l][r][i][0] < INF) {
                    ans = max(ans, i);
                    // cerr << l << ' ' << r << ' ' << dp[l][r][i][0] << endl;
                }
                if (dp[l][r][i][1] < INF) ans = max(ans, i);
            }
        }
    }
    cout << ans;
}
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
    int test = 1;
    // cin >> test;
    while(test--) {
        read();
        solve();
    }
    return 0;
}

Compilation message (stderr)

ho_t3.cpp: In function 'int main()':
ho_t3.cpp:81:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
ho_t3.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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