oj.uz

Submission #964301

# Submission time Handle Problem Language Result Execution time Memory
964301 2024-04-16T15:24:58 Z Nhoksocqt1 Sequence (APIO23_sequence) C++17
47 / 100
 1481 ms 53692 KB 
#ifndef Nhoksocqt1
    #include "sequence.h"
#endif // Nhoksocqt1
#include<bits/stdc++.h>
using namespace std;

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> ii;

template<class X, class Y>
	inline bool maximize(X &x, const Y &y) {return (x < y ? x = y, 1 : 0);}
template<class X, class Y>
	inline bool minimize(X &x, const Y &y) {return (x > y ? x = y, 1 : 0);}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 500005;

vector<int> B[MAXN];
int fen[2 * MAXN], fenp[2 * MAXN];
int val[MAXN], cnt[MAXN], nArr;

int sub2(void) {
    int res(1);
    for (int l = 1; l <= nArr; ++l) {
        set<int> Set;
        int pos(val[l]), cntPos(1);
        Set.insert(pos);
        ++cnt[pos];

        for (int r = l + 1; r <= nArr; ++r) {
            cntPos += (val[r] <= pos);
            if(++cnt[val[r]] == 1)
                Set.insert(val[r]);

            while(cntPos < (r - l + 1) / 2 + 1) {
                auto it = Set.lower_bound(pos); ++it;
                assert(it != Set.end());
                pos = *it;
                cntPos += cnt[pos];
            }

            while(cntPos - cnt[pos] >= (r - l + 1) / 2 + 1) {
                cntPos -= cnt[pos];
                auto it = Set.lower_bound(pos);
                assert(it != Set.begin()); --it;
                pos = *it;
            }

            //cout << l << ' ' << r << ' ' << pos << ' ' << cntPos << '\n';
            res = max(res, cnt[pos]);
            if((r - l + 1) % 2 == 0 && cntPos - cnt[pos] >= (r - l + 1) / 2) {
                auto it = Set.lower_bound(pos);
                assert(it != Set.begin()); --it;
                res = max(res, cnt[*it]);
            }
        }

        for (int r = l; r <= nArr; ++r)
            --cnt[val[r]];
    }

    return res;
}

int sub3(void) {
    int res(0);
    for (int i = 1; i <= nArr; ) {
        int j(i);
        while(j <= nArr && val[j] == val[i])
            ++j;

        res = max(res, j - i);
        i = j;
    }

    for (int i = 1; i <= nArr; ++i)
        ++cnt[val[i]];

    int j(nArr);
    for (int i = 1; i <= j; ++i) {
        if(i > 1 && val[i] == val[i - 1])
            continue;

        while(j > i && val[j] < val[i])
            --cnt[val[j--]];

        if(j > i && val[i] == val[j]) {
            int cntPos = cnt[val[i]];
            if(cnt[val[i]] + i - 1 + nArr - j >= (nArr + 1) / 2)
                res = max(res, cnt[val[i]]);
        }
    }

    return res;
}

void modify(int fen[], int i, int v) {
    for (i += nArr + 1; i <= 2 * nArr + 1; i += i & -i)
        fen[i] += v;
}

int get(int fen[], int i) {
    int res(0);
    for (i += nArr + 1; i > 0; i -= i & -i)
        res += fen[i];

    return res;
}

bool check4(int minCnt, int x) {
    for (int i = 1; i <= 2 * nArr; ++i)
        fen[i] = fenp[i] = 0;

    ll res(0);
    int j(1), cnt(0), sumx(0), sumpx(0), sumxj(0), sumpxj(0);
    for (int i = 1; i <= nArr; ++i) {
        cnt += (val[i] == x);
        while(j <= i && cnt >= minCnt) {
            cnt -= (val[j] == x);
            modify(fen, sumxj, +1);
            modify(fenp, sumpxj, +1);
            sumxj += 2 * (val[j] <= x) - 1;
            sumpxj += 2 * (val[j] < x) - 1;
            ++j;
        }

        sumx += 2 * (val[i] <= x) - 1;
        sumpx += 2 * (val[i] < x) - 1;
        res += get(fen, sumx) - get(fenp, sumpx);
    }

    return (res > 0);
}

int sub4(void) {
    int res(1);
    for (int i = 1; i <= 3; ++i) {
        int l(2), r(nArr);
        while(l <= r) {
            int mid = (l + r) >> 1;
            if(check4(mid, i)) {
                res = max(res, mid);
                l = mid + 1;
            } else {
                r = mid - 1;
            }
        }
    }

    return res;
}

struct SegNode {
    int minv, maxv, lz;
} seg[4 * MAXN];

inline void pushDown(int id) {
    int &lz(seg[id].lz);

    id <<= 1;
    seg[id] = {seg[id].minv + lz, seg[id].maxv + lz, seg[id].lz + lz};
    seg[id | 1] = {seg[id | 1].minv + lz, seg[id | 1].maxv + lz, seg[id | 1].lz + lz};
    lz = 0;
}

void update(int id, int l, int r, int u, int v, int k) {
    if(u <= l && r <= v) {
        seg[id] = {seg[id].minv + k, seg[id].maxv + k, seg[id].lz + k};
        return;
    }

    if(seg[id].lz)
        pushDown(id);

    int mid = (l + r) >> 1;
    if(mid >= u)
        update(id << 1, l, mid, u, v, k);

    if(mid + 1 <= v)
        update(id << 1 | 1, mid + 1, r, u, v, k);

    seg[id].minv = min(seg[id << 1].minv, seg[id << 1 | 1].minv);
    seg[id].maxv = max(seg[id << 1].maxv, seg[id << 1 | 1].maxv);
}

ii query(int id, int l, int r, int u, int v) {
    if(u <= l && r <= v)
        return make_pair(seg[id].minv, seg[id].maxv);

    if(seg[id].lz)
        pushDown(id);

    ii res = {1e9, -1e9};
    int mid = (l + r) >> 1;
    if(mid >= u)
        res = query(id << 1, l, mid, u, v);

    if(mid + 1 <= v) {
        ii qr = query(id << 1 | 1, mid + 1, r, u, v);
        res = {min(res.fi, qr.fi), max(res.se, qr.se)};
    }

    return res;
}

int sub5(void) {
    for (int i = 1; i <= nArr; ++i) {
        B[val[i]].push_back(i);
        update(1, 1, nArr, i, i, -i);
    }

    int res(1);
    for (int i = 1; i <= nArr; ++i) {
        if(!sz(B[i]))
            continue;

        for (int it = 0; it < sz(B[i]); ++it) {
            int j(B[i][it]);
            update(1, 1, nArr, j, nArr, +2);
        }

        if(sz(B[i]) != 2)
            continue;

        int l = B[i][0], r = B[i][1];
        ii qrL = (l > 1) ? query(1, 1, nArr, 1, l - 1) : ii(1e9, -1e9), qrR = query(1, 1, nArr, r, nArr);
        qrL.fi = min(qrL.fi, 0), qrL.se = max(qrL.se, 0);

        //cout << i << ' ' << l << ' ' << r << ' ' << qrL.fi << ' ' << qrL.se << ' ' << qrR.fi << ' ' << qrR.se << '\n';
        if(qrR.se - qrL.fi >= 0 && qrR.fi - qrR.se <= 1) {
            res = 2;
            break;
        }
    }

    return res;
}

int sequence(int _N, vector<int> _A) {
    nArr = _N;
    bool check5(1);
    for (int i = 1; i <= nArr; ++i) {
        val[i] = _A[i - 1];
        check5 &= (++cnt[val[i]] <= 2);
    }

    bool check3(1);
    for (int i = 1; i <= nArr; ++i) {
        check3 &= (i <= 2 || val[i - 2] <= val[i - 1] || val[i - 2] >= val[i - 1] && val[i - 1] >= val[i]);
        cnt[i] = 0;
    }

    //cout << sub5() << '\n';
    if(nArr <= 2000) {
        return sub2();
    } else
        if(check3) {
            return sub3();
        } else
            if(*max_element(val + 1, val + nArr + 1) <= 3) {
                return sub4();
            } else
                if(check5) {
                    return sub5();
                }
}

#ifdef Nhoksocqt1

int main(void) {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    #define TASK "sequence"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    vector<int> _A;
    int _N;
    cin >> _N;

    _A.resize(_N);
    //vector<int> _B; for (int i = 0; sz(_B) < _N; ++i) {int x = Random(1, 2); _B.push_back(i + 1); if(sz(_B) < _N && x > 1) _B.push_back(i + 1); } shuffle(_B.begin(), _B.end(), rng);
    for (int i = 0; i < _N; ++i) {
        cin >> _A[i];
        //_A[i] = _B[i]; cout << _A[i] << " \n"[i + 1 == _N];
    }

    int ans = sequence(_N, _A);
    cout << "ANSWER: " << ans << '\n';

    return 0;
}

#endif // Nhoksocqt1

Compilation message

sequence.cpp: In function 'int sub3()':
sequence.cpp:96:17: warning: unused variable 'cntPos' [-Wunused-variable]
   96 |             int cntPos = cnt[val[i]];
      |                 ^~~~~~
sequence.cpp: In function 'int sequence(int, std::vector<int>)':
sequence.cpp:257:83: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  257 |         check3 &= (i <= 2 || val[i - 2] <= val[i - 1] || val[i - 2] >= val[i - 1] && val[i - 1] >= val[i]);
      |                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:274:1: warning: control reaches end of non-void function [-Wreturn-type]
  274 | }
      | ^

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16444 KB Output is correct
2 Correct 5 ms 16220 KB Output is correct
3 Correct 4 ms 16224 KB Output is correct
4 Correct 5 ms 16700 KB Output is correct
5 Correct 5 ms 16220 KB Output is correct
6 Correct 5 ms 16220 KB Output is correct
7 Correct 4 ms 16220 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 4 ms 16220 KB Output is correct
10 Correct 5 ms 16452 KB Output is correct
11 Correct 5 ms 16308 KB Output is correct
12 Correct 5 ms 16220 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16444 KB Output is correct
2 Correct 5 ms 16220 KB Output is correct
3 Correct 4 ms 16224 KB Output is correct
4 Correct 5 ms 16700 KB Output is correct
5 Correct 5 ms 16220 KB Output is correct
6 Correct 5 ms 16220 KB Output is correct
7 Correct 4 ms 16220 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 4 ms 16220 KB Output is correct
10 Correct 5 ms 16452 KB Output is correct
11 Correct 5 ms 16308 KB Output is correct
12 Correct 5 ms 16220 KB Output is correct
13 Correct 231 ms 16520 KB Output is correct
14 Correct 212 ms 16476 KB Output is correct
15 Correct 30 ms 16220 KB Output is correct
16 Correct 25 ms 16480 KB Output is correct
17 Correct 12 ms 16480 KB Output is correct
18 Correct 212 ms 16560 KB Output is correct
19 Correct 179 ms 16472 KB Output is correct
20 Correct 162 ms 16512 KB Output is correct
21 Correct 197 ms 16632 KB Output is correct
22 Correct 200 ms 16476 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16444 KB Output is correct
2 Correct 48 ms 25552 KB Output is correct
3 Correct 53 ms 25548 KB Output is correct
4 Correct 37 ms 23400 KB Output is correct
5 Correct 46 ms 25564 KB Output is correct
6 Correct 51 ms 25416 KB Output is correct
7 Correct 39 ms 23636 KB Output is correct
8 Correct 50 ms 23628 KB Output is correct
9 Correct 37 ms 23224 KB Output is correct

Subtask #4
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 16220 KB Output is correct
2 Correct 1394 ms 29548 KB Output is correct
3 Correct 1481 ms 29552 KB Output is correct
4 Correct 1468 ms 29552 KB Output is correct
5 Correct 1377 ms 29548 KB Output is correct
6 Correct 750 ms 29548 KB Output is correct

Subtask #5
0.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 354 ms 53692 KB Output is correct
2 Correct 338 ms 53684 KB Output is correct
3 Correct 198 ms 53080 KB Output is correct
4 Correct 201 ms 53084 KB Output is correct
5 Correct 230 ms 49560 KB Output is correct
6 Correct 298 ms 49680 KB Output is correct
7 Incorrect 256 ms 48576 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #6
0.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16444 KB Output is correct
2 Correct 5 ms 16220 KB Output is correct
3 Correct 4 ms 16224 KB Output is correct
4 Correct 5 ms 16700 KB Output is correct
5 Correct 5 ms 16220 KB Output is correct
6 Correct 5 ms 16220 KB Output is correct
7 Correct 4 ms 16220 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 4 ms 16220 KB Output is correct
10 Correct 5 ms 16452 KB Output is correct
11 Correct 5 ms 16308 KB Output is correct
12 Correct 5 ms 16220 KB Output is correct
13 Correct 231 ms 16520 KB Output is correct
14 Correct 212 ms 16476 KB Output is correct
15 Correct 30 ms 16220 KB Output is correct
16 Correct 25 ms 16480 KB Output is correct
17 Correct 12 ms 16480 KB Output is correct
18 Correct 212 ms 16560 KB Output is correct
19 Correct 179 ms 16472 KB Output is correct
20 Correct 162 ms 16512 KB Output is correct
21 Correct 197 ms 16632 KB Output is correct
22 Correct 200 ms 16476 KB Output is correct
23 Incorrect 40 ms 22032 KB Output isn't correct
24 Halted 0 ms 0 KB -

Subtask #7
0.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16444 KB Output is correct
2 Correct 5 ms 16220 KB Output is correct
3 Correct 4 ms 16224 KB Output is correct
4 Correct 5 ms 16700 KB Output is correct
5 Correct 5 ms 16220 KB Output is correct
6 Correct 5 ms 16220 KB Output is correct
7 Correct 4 ms 16220 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 4 ms 16220 KB Output is correct
10 Correct 5 ms 16452 KB Output is correct
11 Correct 5 ms 16308 KB Output is correct
12 Correct 5 ms 16220 KB Output is correct
13 Correct 231 ms 16520 KB Output is correct
14 Correct 212 ms 16476 KB Output is correct
15 Correct 30 ms 16220 KB Output is correct
16 Correct 25 ms 16480 KB Output is correct
17 Correct 12 ms 16480 KB Output is correct
18 Correct 212 ms 16560 KB Output is correct
19 Correct 179 ms 16472 KB Output is correct
20 Correct 162 ms 16512 KB Output is correct
21 Correct 197 ms 16632 KB Output is correct
22 Correct 200 ms 16476 KB Output is correct
23 Correct 48 ms 25552 KB Output is correct
24 Correct 53 ms 25548 KB Output is correct
25 Correct 37 ms 23400 KB Output is correct
26 Correct 46 ms 25564 KB Output is correct
27 Correct 51 ms 25416 KB Output is correct
28 Correct 39 ms 23636 KB Output is correct
29 Correct 50 ms 23628 KB Output is correct
30 Correct 37 ms 23224 KB Output is correct
31 Correct 1394 ms 29548 KB Output is correct
32 Correct 1481 ms 29552 KB Output is correct
33 Correct 1468 ms 29552 KB Output is correct
34 Correct 1377 ms 29548 KB Output is correct
35 Correct 750 ms 29548 KB Output is correct
36 Correct 354 ms 53692 KB Output is correct
37 Correct 338 ms 53684 KB Output is correct
38 Correct 198 ms 53080 KB Output is correct
39 Correct 201 ms 53084 KB Output is correct
40 Correct 230 ms 49560 KB Output is correct
41 Correct 298 ms 49680 KB Output is correct
42 Incorrect 256 ms 48576 KB Output isn't correct
43 Halted 0 ms 0 KB -