oj.uz

Submission #964304

# Submission time Handle Problem Language Result Execution time Memory
964304 2024-04-16T15:28:08 Z Nhoksocqt1 Sequence (APIO23_sequence) C++17
60 / 100
 1482 ms 50484 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 - qrL.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 16220 KB Output is correct
2 Correct 4 ms 16220 KB Output is correct
3 Correct 5 ms 16220 KB Output is correct
4 Correct 5 ms 16216 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 5 ms 16460 KB Output is correct
7 Correct 4 ms 16216 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 6 ms 16216 KB Output is correct
10 Correct 4 ms 16220 KB Output is correct
11 Correct 4 ms 16220 KB Output is correct
12 Correct 4 ms 16220 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16220 KB Output is correct
2 Correct 4 ms 16220 KB Output is correct
3 Correct 5 ms 16220 KB Output is correct
4 Correct 5 ms 16216 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 5 ms 16460 KB Output is correct
7 Correct 4 ms 16216 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 6 ms 16216 KB Output is correct
10 Correct 4 ms 16220 KB Output is correct
11 Correct 4 ms 16220 KB Output is correct
12 Correct 4 ms 16220 KB Output is correct
13 Correct 212 ms 16476 KB Output is correct
14 Correct 201 ms 16504 KB Output is correct
15 Correct 31 ms 16448 KB Output is correct
16 Correct 26 ms 16220 KB Output is correct
17 Correct 14 ms 16472 KB Output is correct
18 Correct 194 ms 16728 KB Output is correct
19 Correct 171 ms 16500 KB Output is correct
20 Correct 151 ms 16472 KB Output is correct
21 Correct 179 ms 16496 KB Output is correct
22 Correct 193 ms 16496 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16220 KB Output is correct
2 Correct 42 ms 22420 KB Output is correct
3 Correct 50 ms 22356 KB Output is correct
4 Correct 35 ms 22364 KB Output is correct
5 Correct 43 ms 22352 KB Output is correct
6 Correct 53 ms 22352 KB Output is correct
7 Correct 44 ms 22608 KB Output is correct
8 Correct 37 ms 22416 KB Output is correct
9 Correct 37 ms 22236 KB Output is correct

Subtask #4
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16220 KB Output is correct
2 Correct 1382 ms 28572 KB Output is correct
3 Correct 1475 ms 28572 KB Output is correct
4 Correct 1482 ms 28568 KB Output is correct
5 Correct 1363 ms 28568 KB Output is correct
6 Correct 759 ms 28572 KB Output is correct

Subtask #5
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 328 ms 50484 KB Output is correct
2 Correct 352 ms 50364 KB Output is correct
3 Correct 209 ms 49648 KB Output is correct
4 Correct 197 ms 49740 KB Output is correct
5 Correct 239 ms 46452 KB Output is correct
6 Correct 299 ms 46480 KB Output is correct
7 Correct 262 ms 45396 KB Output is correct
8 Correct 251 ms 48200 KB Output is correct

Subtask #6
0.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16220 KB Output is correct
2 Correct 4 ms 16220 KB Output is correct
3 Correct 5 ms 16220 KB Output is correct
4 Correct 5 ms 16216 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 5 ms 16460 KB Output is correct
7 Correct 4 ms 16216 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 6 ms 16216 KB Output is correct
10 Correct 4 ms 16220 KB Output is correct
11 Correct 4 ms 16220 KB Output is correct
12 Correct 4 ms 16220 KB Output is correct
13 Correct 212 ms 16476 KB Output is correct
14 Correct 201 ms 16504 KB Output is correct
15 Correct 31 ms 16448 KB Output is correct
16 Correct 26 ms 16220 KB Output is correct
17 Correct 14 ms 16472 KB Output is correct
18 Correct 194 ms 16728 KB Output is correct
19 Correct 171 ms 16500 KB Output is correct
20 Correct 151 ms 16472 KB Output is correct
21 Correct 179 ms 16496 KB Output is correct
22 Correct 193 ms 16496 KB Output is correct
23 Incorrect 36 ms 21584 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 16220 KB Output is correct
2 Correct 4 ms 16220 KB Output is correct
3 Correct 5 ms 16220 KB Output is correct
4 Correct 5 ms 16216 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 5 ms 16460 KB Output is correct
7 Correct 4 ms 16216 KB Output is correct
8 Correct 4 ms 16220 KB Output is correct
9 Correct 6 ms 16216 KB Output is correct
10 Correct 4 ms 16220 KB Output is correct
11 Correct 4 ms 16220 KB Output is correct
12 Correct 4 ms 16220 KB Output is correct
13 Correct 212 ms 16476 KB Output is correct
14 Correct 201 ms 16504 KB Output is correct
15 Correct 31 ms 16448 KB Output is correct
16 Correct 26 ms 16220 KB Output is correct
17 Correct 14 ms 16472 KB Output is correct
18 Correct 194 ms 16728 KB Output is correct
19 Correct 171 ms 16500 KB Output is correct
20 Correct 151 ms 16472 KB Output is correct
21 Correct 179 ms 16496 KB Output is correct
22 Correct 193 ms 16496 KB Output is correct
23 Correct 42 ms 22420 KB Output is correct
24 Correct 50 ms 22356 KB Output is correct
25 Correct 35 ms 22364 KB Output is correct
26 Correct 43 ms 22352 KB Output is correct
27 Correct 53 ms 22352 KB Output is correct
28 Correct 44 ms 22608 KB Output is correct
29 Correct 37 ms 22416 KB Output is correct
30 Correct 37 ms 22236 KB Output is correct
31 Correct 1382 ms 28572 KB Output is correct
32 Correct 1475 ms 28572 KB Output is correct
33 Correct 1482 ms 28568 KB Output is correct
34 Correct 1363 ms 28568 KB Output is correct
35 Correct 759 ms 28572 KB Output is correct
36 Correct 328 ms 50484 KB Output is correct
37 Correct 352 ms 50364 KB Output is correct
38 Correct 209 ms 49648 KB Output is correct
39 Correct 197 ms 49740 KB Output is correct
40 Correct 239 ms 46452 KB Output is correct
41 Correct 299 ms 46480 KB Output is correct
42 Correct 262 ms 45396 KB Output is correct
43 Correct 251 ms 48200 KB Output is correct
44 Incorrect 36 ms 21584 KB Output isn't correct
45 Halted 0 ms 0 KB -