Submission #875002

#	Time	Username	Problem	Language	Result	Execution time	Memory
875002		efedmrlr	Crossing (JOI21_crossing)	C++17	0 / 100	91 ms	204884 KiB

Main

#include <bits/stdc++.h>

using namespace std;

#define int long long int
#define MP make_pair
#define pb push_back
#define REP(i,n) for(int (i) = 0; (i)<(n); (i)++)

void fastio() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
}

const int N = 3e5+5;
const int MOD = 1e9+7;
const int INF = 1e12;
const int M = 1e6+5;
const long double EPS = 0.00001;
 
int n,m,q,d;
vector<int> dp, b;
vector<array<int,2> > a;
queue<array<int,2> > ques[N];
vector<int> vis(N, 0);
struct SegTree {
    int sz;
    vector<int> data;
    SegTree(int sz) {
        this->sz = sz;
        data.assign(4*(sz + 2), -INF);

    }
    void update(int tl, int tr ,int v, int ind, int val) {
        if(tl == tr) {
            data[v] = val;
            return;
        }
        int tm = (tl + tr) >> 1;
        if(ind <= tm) {
            update(tl, tm, v*2, ind, val);
        }
        else {
            update(tm + 1, tr, v*2+1, ind, val);
        }
        data[v] = max(data[v*2], data[v*2+1]);
    }
    void update(int ind ,int val) {
        update(0, sz, 1, ind ,val);
    }
    int query(int tl, int tr, int v, int l, int r) {
        if(tl >= l && tr <= r) return data[v];
        if(tl > r || tr < l) {
            return -INF;
        }
        int tm = (tl + tr) >> 1;
        return max(query(tl, tm, v*2, l, r) , query(tm + 1, tr, v*2+1, l, r));
    }
    int query(int l, int r) {
        return query(0, sz, 1, l, r);
    }
};

struct IndexedSeg {
    int sz;
    vector<array<int,2> > data;
    IndexedSeg(int sz) {
        this->sz = sz;
        data.assign(4*(sz + 2), {-INF, -INF});

    }
    void update(int tl, int tr ,int v, int ind, int val) {
        if(tl == tr) {
            data[v] = {val, tl};
            return;
        }
        int tm = (tl + tr) >> 1;
        if(ind <= tm) {
            update(tl, tm, v*2, ind, val);
        }
        else {
            update(tm + 1, tr, v*2+1, ind, val);
        }
        data[v] = max(data[v*2], data[v*2+1]);
    }
    void update(int ind ,int val) {
        update(0, sz, 1, ind ,val);
    }
    array<int,2>  query(int tl, int tr, int v, int l, int r) {
        if(tl >= l && tr <= r) return data[v];
        if(tl > r || tr < l) {
            return {-INF, -INF};
        }
        int tm = (tl + tr) >> 1;
        return max(query(tl, tm, v*2, l, r) , query(tm + 1, tr, v*2+1, l, r));
    }
    array<int,2> query(int l, int r) {
        return query(0, sz, 1, l, r);
    }
};

void operate(SegTree &st, int ind ,int order) {
    while(ques[ind].size() && ques[ind].front()[0] <= dp[order]) {
        ques[ind].pop();
    }
    ques[ind].push({dp[order], order});
    st.update(ind, ques[ind].front()[0]);
}
void remove_el(SegTree &st, int ind) {
    while(ques[ind].size() && vis[ ques[ind].front()[1] ]) {
        ques[ind].pop();
        
    }
    if(ques[ind].size()) {
        st.update(ind, ques[ind].front()[0]);       
    }
    else {
        st.update(ind, -INF);
    }

}

void compress() {
    sort(a.begin(), a.end());
    int last = -1;
    int cur = 0;
    for(int i = 0; i<n; i++) {
        if(a[i][0] == last) {
            a[i][0] = cur;
        }
        else {
            last = a[i][0];
            cur++;
            a[i][0] = cur;
        }
    }
    b.assign(n+1, 0);
    for(auto c : a) {
        b[c[1]] = c[0];
    }

}
signed main() {
    fastio();
    cin>>n>>d;
    a.resize(n);
    dp.assign(n + 1, 1);
    REP(i,n) {
        cin>>a[i][0];
        a[i][1] = i + 1;
    }
    
    compress();
    SegTree stmain(n + 5); 
    IndexedSeg stsec(n + 5);
    dp[n] = 1;
    operate(stmain, b[n], n);
    stsec.update(n, -b[n]);
    for(int i = n - 1; i>=1; i--) {
        dp[i] = stmain.query(b[i] + 1, n + 3) + 1;
        dp[i] = max(dp[i] , 1ll);
        operate(stmain, b[i], i);
        if(i + d <= n) {
            array<int,2> last = stsec.query(i + d, n+2);
            last[0] = abs(last[0]);
            while(last[0] <= b[i]) {
                vis[last[1]] = 1;
                remove_el(stmain, b[last[1]]);
                stsec.update(last[1], -INF);
                last = stsec.query(i + d, n+2);
                last[0] = abs(last[0]);
            }
        }
        stsec.update(i, -b[i]);

    }
    
    int ans = 0;
    for(int i = 1 ;i<=n;i++) {
        ans = max(ans , dp[i]);
    }
    cout<<ans<<"\n";

}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:8:26: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
    8 | #define REP(i,n) for(int (i) = 0; (i)<(n); (i)++)
      |                          ^
Main.cpp:148:5: note: in expansion of macro 'REP'
  148 |     REP(i,n) {
      |     ^~~

• Subtask 1: 0 / 3
• Subtask 2: 0 / 23
• Subtask 3: 0 / 23
• Subtask 4: 0 / 51