제출 #785415

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
785415		vjudge1	송신탑 (IOI22_towers)	C++17	4 / 100	4094 ms	3472 KiB

towers

#include "towers.h"
#include <bits/stdc++.h>
using namespace std;
int N, p;
vector<int> H, pfs(N + 1);
void init(int n, vector<int> h) {
    N = n, H = h, p = -1;
    for (int i = 0; i < N; i++) {
        if ((i == 0 || H[i] > H[i - 1]) && (i == N - 1 || H[i] > H[i + 1])) {
            p = i;
        }
    }
    for (int i = 0; i < p; i++) {
        if (H[i] > H[i + 1]) {
            p = -1;
            return;
        }
    }
    for (int i = p + 1; i < N; i++) {
        if (H[i - 1] < H[i]) {
            p = -1;
            return;
        }
    }
    pfs.resize(N + 1);
    for (int i = 0; i < N; i++) {
        pfs[i + 1] = pfs[i] + ((i == 0 || H[i] < H[i - 1]) && (i == N - 1 || H[i] < H[i + 1]));
    }
}
int max_towers(int L, int R, int D) {
    if (L == R) {
        return 1;
    }
    if (p != -1) {
        int l = upper_bound(H.begin(), H.begin() + p, H[p] - D) - H.begin() - 1;
        int r = lower_bound(H.begin() + p, H.end(), H[p] - D, [&](int x, int y) {return x > y;}) - H.begin();
        return (L <= l && r <= R) ? 2 : 1;
    }
    if (D == 1) {
        int ans = pfs[R] - pfs[L + 1];
        if (H[L] < H[L + 1]) {
            ans++;
        }
        if (H[R] < H[R - 1]) {
            ans++;
        }
        return ans;
    }
    vector<int> lg(N + 1);
    for (int i = 2; i <= N; i++) {
        lg[i] = lg[i / 2] + 1;
    }
    vector st(N, vector<int>(lg[N] + 1));
    for (int i = 0; i < N; i++) {
        st[i][0] = H[i];
    }
    for (int j = 0; j < lg[N]; j++) {
        for (int i = 0; i + (2 << j) <= N; i++) {
            st[i][j + 1] = max(st[i][j], st[i + (1 << j)][j]);
        }
    }
    auto query = [&](int l, int r) {
        if (l == r) {
            return 0;
        }
        int k = lg[r - l];
        return max(st[l][k], st[r - (1 << k)][k]);
    };
    vector<int> l(N, -1), r(N, N);
    for (int i = 0; i < N; i++) {
        if (query(0, i) >= H[i] + D) {
            int lo = 0, hi = i - 1;
            while (lo < hi) {
                int mi = (lo + hi + 1) / 2;
                if (query(mi, i) >= H[i] + D) {
                    lo = mi;
                } else {
                    hi = mi - 1;
                }
            }
            l[i] = lo;
        }
        if (query(i + 1, N) >= H[i] + D) {
            int lo = i + 1, hi = N - 1;
            while (lo < hi) {
                int mi = (lo + hi) / 2;
                if (query(i + 1, mi + 1) >= H[i] + D) {
                    hi = mi;
                } else {
                    lo = mi + 1;
                }
            }
            r[i] = lo;
        }
    }
    vector<int> dp(N + 1), t(N + 1);
    for (int i = L; i <= R; i++) {
        t[i + 1] = max(t[i + 1], t[i]);
        dp[i + 1] = max(dp[i], t[l[i] + 1] + 1);
        if (r[i] < N) {
            t[r[i] + 1] = max(t[r[i] + 1], dp[i + 1]);
        }
    }
    return dp[R + 1];
}

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