Submission #253767

#	Time	Username	Problem	Language	Result	Execution time	Memory
253767		Sorting	Collecting Stamps 3 (JOI20_ho_t3)	C++14	100 / 100	62 ms	42360 KiB

ho_t3

#include <bits/stdc++.h>

using namespace std;

const int k_N = 200 + 3;

struct Node{
    int pos1, pos2;
    bool which;
    int cnt;

    Node(){}
    Node(int pos1, int pos2, bool which, int cnt){
        this->pos1 = pos1;
        this->pos2 = pos2;
        this->which = which;
        this->cnt = cnt;
    }
};

int n, l, x[k_N], t[k_N];
int max_t = 0;

int dist[k_N][k_N][2][k_N];
bool in_q[k_N][k_N][2][k_N];
int ans = 0;

queue<Node> pq;

void try_add(int pos1, int pos2, bool which, int cnt, int time){
    if(dist[pos1][pos2][which][cnt] > time){
        dist[pos1][pos2][which][cnt] = time;
        if(!in_q[pos1][pos2][which][cnt]){
            pq.push({pos1, pos2, which, cnt});
            in_q[pos1][pos2][which][cnt] = true;
        }
    }
}

void dijkstra(){
    for(int pos1 = 0; pos1 <= n + 1; ++pos1)
        for(int pos2 = pos1; pos2 <= n + 1; ++pos2)
            for(short which = 0; which <= 1; ++which)
                for(int cnt = 0; cnt <= n; ++cnt)
                    dist[pos1][pos2][which][cnt] = max_t;

    pq.push({0, n + 1, false, 0});
    dist[0][n + 1][false][0] = 0;
    in_q[0][n + 1][false][0] = true;

    while(!pq.empty()){
        auto [pos1, pos2, which, cnt] = pq.front();
        pq.pop();

        int time = dist[pos1][pos2][which][cnt];
        in_q[pos1][pos2][which][cnt] = false;

        ans = max(ans, cnt);

        if(pos1 + 1 == pos2) continue;

        int new_pos1, new_pos2, new_which, new_cnt, new_time;
        if(!which){
            new_time = time + x[pos1 + 1] - x[pos1];
            new_cnt = cnt + (new_time <= t[pos1 + 1]);
            new_pos1 = pos1 + 1;
            new_pos2 = pos2;
            new_which = false;

            try_add(new_pos1, new_pos2, new_which, new_cnt, new_time);
        }
        else{
            new_time = time + x[pos2] - x[pos2 - 1];
            new_cnt = cnt + (new_time <= t[pos2 - 1]);
            new_pos1 = pos1;
            new_pos2 = pos2  - 1;
            new_which = true;

            try_add(new_pos1, new_pos2, new_which, new_cnt, new_time);
        }

        if(!which){
            new_time = time + x[pos1] + l - x[pos2 - 1];
            new_cnt = cnt + (new_time <= t[pos2 - 1]);
            new_pos1 = pos1;
            new_pos2 = pos2 - 1;
            new_which = true;

            try_add(new_pos1, new_pos2, new_which, new_cnt, new_time);
        }
        else{
            new_time = time + x[pos1 + 1] + l - x[pos2];
            new_cnt = cnt + (new_time <= t[pos1 + 1]);
            new_pos1 = pos1 + 1;
            new_pos2 = pos2;
            new_which = false;

            try_add(new_pos1, new_pos2, new_which, new_cnt, new_time);
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> l;

    x[0] = 0;
    for(int i = 1; i <= n; ++i)
        cin >> x[i];
    x[n + 1] = l;

    t[0] = 0;
    for(int i = 1; i <= n; ++i){
        cin >> t[i];
        max_t = max(max_t, t[i]);
    }
    t[n + 1] = 0;

    max_t++;
    dijkstra();
    //ans -= 2;

    cout << ans << "\n";
}

Compilation message (stderr)

ho_t3.cpp: In function 'void dijkstra()':
ho_t3.cpp:52:14: warning: decomposition declaration only available with -std=c++1z or -std=gnu++1z
         auto [pos1, pos2, which, cnt] = pq.front();
              ^

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