Submission #1063147

#	Time	Username	Problem	Language	Result	Execution time	Memory
1063147		Whisper	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	108 ms	129724 KiB

ho_t3

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define REPD(i, a) for (int i = (a) - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)


constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
int nArr, L;
#define MAX                 202
int A[MAX], T[MAX];

//min DP[l][r][picked][where] = time

//where = 0: clock wise
//where = 1: counter clock wise

int dp[MAX][MAX][MAX][2];

void process(void){
    cin >> nArr >> L;
    for (int i = 1; i <= nArr; ++i) cin >> A[i];
    for (int i = 1; i <= nArr; ++i) cin >> T[i];
    A[nArr + 1] = L;
    memset(dp, 0x3f, sizeof dp);
    REP(i, 2) dp[0][0][0][i] = 0;

    REP(l, nArr) REP(r, nArr) REP(picked, nArr){
        if(l + r + 1 > nArr) continue;
        int cur = dp[l][r][picked][1];

        bool can_pick = 0;

        can_pick = (cur + (A[r + 1] - A[r]) <= T[r + 1]);
        minimize(dp[l][r + 1][picked + can_pick][1], cur + (A[r + 1] - A[r]));

        can_pick = (cur + (A[r] + L - A[nArr - l]) <= T[nArr - l]);
        minimize(dp[l + 1][r][picked + can_pick][0], cur + (A[r] + L - A[nArr - l]));

            cur = dp[l][r][picked][0];

        can_pick = (cur + (A[nArr - l + 1] - A[nArr - l]) <= T[nArr - l]);
        minimize(dp[l + 1][r][picked + can_pick][0], cur + (A[nArr - l + 1] - A[nArr - l]));
        can_pick = (cur + (L - A[nArr - l + 1] + A[r + 1]) <= T[r + 1]);
        minimize(dp[l][r + 1][picked + can_pick][1], cur + (L - A[nArr - l + 1] + A[r + 1]));
    }

    FORD(picked, 0, nArr) FOR(l, 0, nArr) FOR(r, 0, nArr) REP(where, 2){
        if(dp[l][r][picked][where] < INF){
            return void(cout << picked);
        }
    }
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    process();
    return (0 ^ 0);
}

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