Submission #516832

#	Time	Username	Problem	Language	Result	Execution time	Memory
516832		nickyrio	Exam (eJOI20_exam)	C++17	100 / 100	106 ms	14480 KiB

exam

#include <bits/stdc++.h>

using namespace std;
#define all(s) s.begin(), s.end() 
const int N = 1e5 + 100;
const int LG = 17;

int a[N], b[N], n, L[N], R[N];
vector<int> e[N];
int BIT[N], RMQ[LG][N], lg2[N];

int query(int u) {
    int ans = 0;
    for(; u > 0; u -= u & -u) ans = max(ans, BIT[u]);
    return ans;
}
void update(int u, int v) {
    for (; u < N; u += u & -u) BIT[u] = max(BIT[u], v);
}

void sub2() {
    for (int i = 2; i <= n; ++i) if (b[i] != b[1]) return;
    int cnt = 0;
    for (int i = 1; i <= n; ++i) if (a[i] == b[1]) {
        for (int j = i - 1; a[j] < a[i]; --j) a[j] = a[i];
        for (int j = i + 1; a[j] < a[i]; ++j) a[j] = a[i];
    }
    for (int i = 1; i <= n; ++i) if (a[i] == b[1]) ++cnt;
    cout << cnt << '\n';
    exit(0);
}

int main() {
    ios::sync_with_stdio(false); cin.tie(NULL);
    cin >> n;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    for (int i = 1; i <= n; ++i) cin >> b[i];
    a[0] = a[n + 1] = 2e9;
    sub2();
    vector<int> Ranking(a + 1, a + n + 1);
    sort(all(Ranking));
    Ranking.resize(unique(all(Ranking)) - Ranking.begin());
    for (int i = 1; i <= n; ++i) {
        a[i] = lower_bound(all(Ranking), a[i]) - Ranking.begin();
        int temp_b = lower_bound(all(Ranking), b[i]) - Ranking.begin();
        if (temp_b != Ranking.size() && Ranking[temp_b] != b[i]) temp_b = Ranking.size();
        b[i] = temp_b;
        e[b[i]].push_back(i);
    }
    for (int i = 1; i <= n; ++i) RMQ[0][i] = a[i];
    for (int i = 2; i <= n; ++i) lg2[i] = lg2[i >> 1] + 1;
    for (int j = 1; j < LG; ++j) {
        for (int i = 1; i + (1 << j) - 1 <= n; ++i) {
            RMQ[j][i] = max(RMQ[j - 1][i], RMQ[j - 1][i + (1 << (j - 1))]);
        }
    }   
    auto getMAX = [&](int l, int r) {
        int d = lg2[r - l + 1];
        return max(RMQ[d][l], RMQ[d][r - (1 << d) + 1]);
    };
    int ans = 0;
    for (int i = 1; i <= n; ++i) {
        int best = 0;
        for (int j : e[a[i]]) {
            int l = j, r = i;
            if (l > r) swap(l, r);
            if (getMAX(l, r) > a[i]) continue;
            best = max(best, query(j - 1)) + 1;
            update(j, best);
            ans = max(ans, best);
        }
        
    }
    cout << ans << '\n';
}

Compilation message (stderr)

exam.cpp: In function 'int main()':
exam.cpp:46:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |         if (temp_b != Ranking.size() && Ranking[temp_b] != b[i]) temp_b = Ranking.size();
      |             ~~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 12 / 12
• Subtask 3: 13 / 13
• Subtask 4: 23 / 23
• Subtask 5: 16 / 16
• Subtask 6: 22 / 22