제출 #628585

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
628585		dqhungdl	송신탑 (IOI22_towers)	C++17	27 / 100	4038 ms	11236 KiB

towers

#include "towers.h"
#include <bits/stdc++.h>
using namespace std;

const int MAX = 1e5 + 5;
int N, lg[MAX], peaks[MAX], maxH[MAX][20];
bool isMountain = true;
vector<int> H;

struct FenwickTree {
    int n;
    vector<int> tree;

    FenwickTree(int _n) {
        n = _n;
        tree.resize(n + 5);
    }

    void update(int idx, int val) {
        idx++;
        for (int i = idx; i <= n; i += i & -i)
            tree[i] = max(tree[i], val);
    }

    int get(int idx) {
        idx++;
        int rs = 0;
        for (int i = idx; i > 0; i -= i & -i)
            rs = max(rs, tree[i]);
        return rs;
    }
};

int get(int l, int r) {
    int k = lg[r - l + 1];
    return max(maxH[l][k], maxH[r - (1 << k) + 1][k]);
}

void init(int _N, vector<int> _H) {
    N = _N, H = _H;
    for (int i = 1; i <= N; i++)
        lg[i] = log2(i);
    for (int i = 0; i < N; i++)
        maxH[i][0] = H[i];
    for (int i = 1; i < N - 1; i++)
        peaks[i] = peaks[i - 1] + (H[i] > max(H[i - 1], H[i + 1]));
    peaks[N - 1] = peaks[N - 2];
    for (int t = 1; t <= 18; t++)
        for (int i = 0; i + (1 << t) - 1 < N; i++)
            maxH[i][t] = max(maxH[i][t - 1], maxH[i + (1 << (t - 1))][t - 1]);
    int id = max_element(H.begin(), H.end()) - H.begin();
    for (int i = id; i > 0 && isMountain; i--)
        isMountain &= (H[i] > H[i - 1]);
    for (int i = id; i < N - 1 && isMountain; i++)
        isMountain &= (H[i] > H[i + 1]);
}

int max_towers(int L, int R, int D) {
    if (isMountain)
        return get(L, R) - D >= max(H[L], H[R]) ? 2 : 1;
    if (D == 1)
        return peaks[R - 1] - peaks[L] + 1;
    vector<int> bl(R - L + 1, -1), br(R - L + 1, R - L + 1);
    for (int i = L; i <= R; i++) {
        int l = L, r = i - 1;
        while (l <= r) {
            int mid = (l + r) / 2;
            if (get(mid, i - 1) - D >= H[i]) {
                bl[i - L] = mid - L;
                l = mid + 1;
            } else
                r = mid - 1;
        }
        l = i + 1, r = R;
        while (l <= r) {
            int mid = (l + r) / 2;
            if (get(i + 1, mid) - D >= H[i]) {
                br[i - L] = mid - L;
                r = mid - 1;
            } else
                l = mid + 1;
        }
    }
    vector<int> f(R - L + 1, 1);
    FenwickTree tree(R - L + 1);
    for (int i = 0; i < R - L + 1; i++) {
        if (bl[i] != -1)
            f[i] = tree.get(bl[i]) + 1;
        tree.update(br[i], f[i]);
    }
    return *max_element(f.begin(), f.end());
}

//int main() {
//    freopen("../_input", "r", stdin);
//    int N, Q;
//    assert(2 == scanf("%d %d", &N, &Q));
//    std::vector<int> H(N);
//    for (int i = 0; i < N; ++i) {
//        assert(1 == scanf("%d", &H[i]));
//    }
//    init(N, H);
//
//    for (int i = 0; i < Q; ++i) {
//        int L, R, D;
//        assert(3 == scanf("%d %d %d", &L, &R, &D));
//        printf("%d\n", max_towers(L, R, D));
//    }
//    return 0;
//}

• Subtask 1: 4 / 4
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23