oj.uz

Submission #964298

# Submission time Handle Problem Language Result Execution time Memory
964298 2024-04-16T15:18:38 Z Nhoksocqt1 Sequence (APIO23_sequence) C++17
47 / 100
 1488 ms 53700 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 = query(1, 1, nArr, 1, l), qrR = query(1, 1, nArr, r, nArr);
        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;
    }

    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; i < _N; ++i) _B.push_back(i / 2 + 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:254:83: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  254 |         check3 &= (i <= 2 || val[i - 2] <= val[i - 1] || val[i - 2] >= val[i - 1] && val[i - 1] >= val[i]);
      |                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:270:1: warning: control reaches end of non-void function [-Wreturn-type]
  270 | }
      | ^

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16220 KB Output is correct
2 Correct 3 ms 16220 KB Output is correct
3 Correct 4 ms 16220 KB Output is correct
4 Correct 5 ms 16220 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 4 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 16476 KB Output is correct
11 Correct 4 ms 16220 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 16220 KB Output is correct
2 Correct 3 ms 16220 KB Output is correct
3 Correct 4 ms 16220 KB Output is correct
4 Correct 5 ms 16220 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 4 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 16476 KB Output is correct
11 Correct 4 ms 16220 KB Output is correct
12 Correct 5 ms 16220 KB Output is correct
13 Correct 223 ms 16516 KB Output is correct
14 Correct 214 ms 16476 KB Output is correct
15 Correct 24 ms 16456 KB Output is correct
16 Correct 25 ms 16476 KB Output is correct
17 Correct 13 ms 16480 KB Output is correct
18 Correct 213 ms 16552 KB Output is correct
19 Correct 175 ms 16504 KB Output is correct
20 Correct 151 ms 16476 KB Output is correct
21 Correct 176 ms 16508 KB Output is correct
22 Correct 185 ms 16476 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 49 ms 25552 KB Output is correct
3 Correct 49 ms 25692 KB Output is correct
4 Correct 35 ms 23376 KB Output is correct
5 Correct 55 ms 25656 KB Output is correct
6 Correct 44 ms 25428 KB Output is correct
7 Correct 41 ms 23768 KB Output is correct
8 Correct 37 ms 23800 KB Output is correct
9 Correct 36 ms 23244 KB Output is correct

Subtask #4
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 16220 KB Output is correct
2 Correct 1395 ms 29556 KB Output is correct
3 Correct 1488 ms 29556 KB Output is correct
4 Correct 1475 ms 29552 KB Output is correct
5 Correct 1361 ms 29552 KB Output is correct
6 Correct 737 ms 29408 KB Output is correct

Subtask #5
0.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 331 ms 53700 KB Output is correct
2 Correct 329 ms 53524 KB Output is correct
3 Correct 201 ms 53076 KB Output is correct
4 Correct 205 ms 52876 KB Output is correct
5 Incorrect 286 ms 49688 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #6
0.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 16220 KB Output is correct
2 Correct 3 ms 16220 KB Output is correct
3 Correct 4 ms 16220 KB Output is correct
4 Correct 5 ms 16220 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 4 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 16476 KB Output is correct
11 Correct 4 ms 16220 KB Output is correct
12 Correct 5 ms 16220 KB Output is correct
13 Correct 223 ms 16516 KB Output is correct
14 Correct 214 ms 16476 KB Output is correct
15 Correct 24 ms 16456 KB Output is correct
16 Correct 25 ms 16476 KB Output is correct
17 Correct 13 ms 16480 KB Output is correct
18 Correct 213 ms 16552 KB Output is correct
19 Correct 175 ms 16504 KB Output is correct
20 Correct 151 ms 16476 KB Output is correct
21 Correct 176 ms 16508 KB Output is correct
22 Correct 185 ms 16476 KB Output is correct
23 Incorrect 49 ms 21960 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 3 ms 16220 KB Output is correct
3 Correct 4 ms 16220 KB Output is correct
4 Correct 5 ms 16220 KB Output is correct
5 Correct 4 ms 16220 KB Output is correct
6 Correct 4 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 16476 KB Output is correct
11 Correct 4 ms 16220 KB Output is correct
12 Correct 5 ms 16220 KB Output is correct
13 Correct 223 ms 16516 KB Output is correct
14 Correct 214 ms 16476 KB Output is correct
15 Correct 24 ms 16456 KB Output is correct
16 Correct 25 ms 16476 KB Output is correct
17 Correct 13 ms 16480 KB Output is correct
18 Correct 213 ms 16552 KB Output is correct
19 Correct 175 ms 16504 KB Output is correct
20 Correct 151 ms 16476 KB Output is correct
21 Correct 176 ms 16508 KB Output is correct
22 Correct 185 ms 16476 KB Output is correct
23 Correct 49 ms 25552 KB Output is correct
24 Correct 49 ms 25692 KB Output is correct
25 Correct 35 ms 23376 KB Output is correct
26 Correct 55 ms 25656 KB Output is correct
27 Correct 44 ms 25428 KB Output is correct
28 Correct 41 ms 23768 KB Output is correct
29 Correct 37 ms 23800 KB Output is correct
30 Correct 36 ms 23244 KB Output is correct
31 Correct 1395 ms 29556 KB Output is correct
32 Correct 1488 ms 29556 KB Output is correct
33 Correct 1475 ms 29552 KB Output is correct
34 Correct 1361 ms 29552 KB Output is correct
35 Correct 737 ms 29408 KB Output is correct
36 Correct 331 ms 53700 KB Output is correct
37 Correct 329 ms 53524 KB Output is correct
38 Correct 201 ms 53076 KB Output is correct
39 Correct 205 ms 52876 KB Output is correct
40 Incorrect 286 ms 49688 KB Output isn't correct
41 Halted 0 ms 0 KB -