Submission #1052590

#	Time	Username	Problem	Language	Result	Execution time	Memory
1052590		underwaterkillerwhale	Sequence (APIO23_sequence)	C++17	0 / 100	27 ms	18568 KiB

sequence

#include <bits/stdc++.h>
#define ll long long
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define MP make_pair
#define fs first
#define se second
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define pb push_back
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(),v.end()

using namespace std;

mt19937_64 rd(chrono :: steady_clock :: now ().time_since_epoch().count());
ll Rand (ll l, ll r) { return uniform_int_distribution<ll> (l, r) (rd); }

const int N = 5e5 + 7;
const int Mod = 1e9 + 7;
const int INF = 1e9 + 7;
const ll BASE = 137;

int n;
int a[N];
vector<int> pos[N];

struct Node {
    int premn, sufmn, premx, sufmx, sum;
};

struct Segment_Tree {
    int m;
    Node st[N << 2] ;

    void init (int n) {
        m = n;
    }
    Node mer (Node lf, Node rt) {
        Node cur;
        cur.sum = lf.sum + rt.sum;
        cur.premn = min(lf.premn, lf.sum + rt.premn);
        cur.premx = max(lf.premx, lf.sum + rt.premx);
        cur.sufmn = min(rt.sufmn, rt.sum + lf.sufmn);
        cur.sufmx = max(rt.sufmx, rt.sum + lf.sufmx);
        return cur;
    }

    void update (int id, int l, int r, int pos, int val) {
        if (l > pos || r < pos)
            return;
        if (l == r) {
            st[id].sum = val;
            st[id].premn = st[id].sufmn = min(val, 0);
            st[id].premx = st[id].sufmx = max(val, 0);
            return;
        }
        int mid = l + r >> 1;
        update (id << 1, l, mid, pos, val);
        update (id << 1 | 1, mid + 1, r, pos, val);
        st[id] = mer(st[id << 1], st[id << 1 | 1]);
    }

    Node get (int id, int l, int r, int u, int v) {
        if (l > v || r < u || u > v) return {0, 0, 0, 0, 0};
        if (l >= u && r <= v) return st[id];
        int mid = l + r >> 1;
        return mer (get (id << 1, l, mid, u, v), get (id << 1 | 1, mid + 1, r, u, v));
    }

    void update (int pos, int val) {
        update (1, 1, m, pos, val);
    }

    Node get (int u, int v) {
        return get (1, 1, m, u, v);
    }
}ST;

bool check (int L, int R, int K) {
    Node prep = ST.get (1, L - 1);
    Node sufp = ST.get (R + 1, n);
    int sum = ST.get (L + 1, R - 1).sum;
    pair<int,int> pre = MP(prep.sufmn, prep.sufmx), suf = MP(sufp.premn, sufp.premx);
    int sL = pre.fs + suf.fs + sum;
    int sR = pre.se + suf.se + sum;
//    if (K >= abs(sum)) return 1;
//    if (K == 4 && L == 0 && R == n + 1) cout <<"hihia: "<<sL <<" "<<sR<<"\n";
    if (sL <= K || K >= sR) return 1;
    return 0;
}

int sequence (int _n, vector<int> _a) {
//void solution () {
//    cin >> n;
//    rep (i, 1, n) {
//        cin >> a[i];
//    }
//    n = _n;
//    rep (i, 1, n) a[i] = _a[i - 1];
    rep (i, 1, n) {
        pos[a[i]].pb(i);
    }
    ST.init(n);
    rep (i, 1, n) ST.update (i, 1);
    int res = 0;
    rep (x, 1, n) {
        vector<int> &curp = pos[x];
        iter (&id, curp) ST.update(id, 0);
        int ptr = 0;
//        cout << x<<":\n";
        rep (i, 0, SZ(curp) - 1) {
            int cur = curp[i];
            if (ptr < i) ptr = i;
            while (ptr < SZ(curp) - 1 && check (cur - 1, curp[ptr + 1] + 1, ptr + 1 - i + 1)) ++ptr;
//            if (x == 3 && i == 0) cout <<"hihi: "<< check (cur - 1, curp[ptr + 1] + 1, 3) <<"\n";
//            cout << i << " "<<ptr <<"\n";
            res = max(res, ptr - i + 1);
        }
        iter (&id, curp)
         ST.update(id, -1);
    }
//    cout << res <<"\n";
    return res;
}

//#define file(name) freopen(name".inp","r",stdin); \
//freopen(name".out","w",stdout);
//int main () {
////    file("c");
//    ios_base :: sync_with_stdio(false); cin.tie(0); cout.tie(0);
//    int num_Test = 1;
////    cin >> num_Test;
//    while (num_Test--)
//        solution();
//}
/*
no bug challenge +2
2 + 8 * 2 - 9

*/

Compilation message (stderr)

sequence.cpp:129:1: warning: multi-line comment [-Wcomment]
  129 | //#define file(name) freopen(name".inp","r",stdin); \
      | ^
sequence.cpp: In member function 'void Segment_Tree::update(int, int, int, int, int)':
sequence.cpp:60:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   60 |         int mid = l + r >> 1;
      |                   ~~^~~
sequence.cpp: In member function 'Node Segment_Tree::get(int, int, int, int, int)':
sequence.cpp:69:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   69 |         int mid = l + r >> 1;
      |                   ~~^~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 17
• Subtask 3: 0 / 7
• Subtask 4: 0 / 12
• Subtask 5: 0 / 13
• Subtask 6: 0 / 22
• Subtask 7: 0 / 18