Submission #367314

#	Time	Username	Problem	Language	Result	Execution time	Memory
367314		piddddgy	Collecting Stamps 3 (JOI20_ho_t3)	C++11	100 / 100	205 ms	245176 KiB

ho_t3

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define cerr if(false) cerr
#define watch(x) cerr << (#x) << " is " << (x) << endl;
#define endl '\n'
#define ld long double
#define int long long
#define pii pair<int, int>
#define fi first
#define se second
#define sz(a) (int)(a).size()
#define all(x) (x).begin(), (x).end()

const int maxn = 250;

int n, l;
int x[maxn], t[maxn];

// [l][r][where][taken] = time
int dp[maxn][maxn][2][maxn];

int mod(int num) {
    return (num+n)%n;
}

int dist(int x, int y) {
    int res = abs(x-y);
    res = min(res, l-res);

    return res;
}

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

    for(int i = 0; i < maxn; i++) {
        for(int j = 0; j < maxn; j++) {
            for(int k = 0; k < 2; k++) {
                for(int l = 0; l < maxn; l++) {
                    dp[i][j][k][l] = 1e18;
                }
            }
        }
    }

    cin >> n >> l;
    for(int i = 1; i <= n; i++) {
        cin >> x[i];
    }

    for(int i = 1; i <= n; i++) {
        cin >> t[i];
    }

    dp[0][0][0][0] = dp[0][0][1][0] = 0;
    n++;
    int ans = 0;

    // length of interval including 0 (top of circle)
    for(int len = 2; len <= n; len++) {
        for(int st = 1-len; st <= 0; st++) {
            int l = mod(st);
            int r = mod(l+len-1);

            for(int i = 0; i <= n; i++) {
                // left, right
                int l2 = mod(l+1);
                int r2 = mod(r-1);

                dp[l][r][0][i] = min({dp[l][r][0][i], dp[l2][r][0][i] + dist(x[l], x[l2]), dp[l2][r][1][i] + dist(x[l], x[r])});
                dp[l][r][1][i] = min({dp[l][r][1][i], dp[l][r2][0][i] + dist(x[r], x[l]), dp[l][r2][1][i] + dist(x[r], x[r2])});

                if(i) {
                    // TAKE LEFT

                    // last take left
                    if(dp[l2][r][0][i-1] + dist(x[l], x[l2]) <= t[l]) {
                        dp[l][r][0][i] = min(dp[l][r][0][i], dp[l2][r][0][i-1] + dist(x[l], x[l2]));
                    }

                    // last take right
                    if(dp[l2][r][1][i-1] + dist(x[l], x[r]) <= t[l]) {
                        dp[l][r][0][i] = min(dp[l][r][0][i], dp[l2][r][1][i-1] + dist(x[l], x[r]));
                    }

                    // TAKE RIGHT

                    // last taken left
                    if(dp[l][r2][0][i-1] + dist(x[l], x[r]) <= t[r]) {
                        dp[l][r][1][i] = min(dp[l][r][1][i], dp[l][r2][0][i-1] + dist(x[l], x[r]));
                    }

                    // last taken right
                    if(dp[l][r2][1][i-1] + dist(x[r2], x[r]) <= t[r]) {
                        dp[l][r][1][i] = min(dp[l][r][1][i], dp[l][r2][1][i-1] + dist(x[r2], x[r]));
                    }
                }

                if(min(dp[l][r][0][i], dp[l][r][1][i]) != 1e18) {
                    ans = max(ans, i);
                }
            }
        }
    }
    cout << ans << endl;
}

/*

[bitmask][current][time] 

9 600 000

6 25
3 4 7 17 21 23
11 7 17 10 8 10
-> 4

5 20
4 5 8 13 17
18 23 15 7 10
-> 5

4 19
3 7 12 14
2 0 5 4
-> 4

10 87
9 23 33 38 42 44 45 62 67 78
15 91 7 27 31 53 12 91 89 46
-> 5

Did you read the bounds?
Did you make typos?
Are there edge cases (N=1?)
Are array sizes proper?
Integer overflow?
DS reset properly between test cases?
Is using long longs causing TLE?
Are you using floating points?
*/

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