Submission #947226

#	Time	Username	Problem	Language	Result	Execution time	Memory
947226		Nhoksocqt1	송신탑 (IOI22_towers)	C++17	4 / 100	4029 ms	12192 KiB

towers

#ifndef Nhoksocqt1
    #include "towers.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 = 100005;

vector<ii> B[MAXN];
int dp[MAXN], nxt[MAXN], prv[MAXN];
int h[MAXN], pos[MAXN], nArr, ksub1;
bool check_sub1;

void init(int _N, vector<int> _H) {
    nArr = _N;
    ksub1 = 1;
    for (int i = 1; i <= nArr; ++i) {
        h[i] = _H[i - 1];
        if(h[ksub1] < h[i])
            ksub1 = i;
    }

    check_sub1 = 1;
    for (int i = 3; i <= nArr; ++i)
        check_sub1 &= (h[i - 2] < h[i - 1] || h[i - 1] > h[i]);
}

struct SegNode {
    int maxv, lz;
} seg[4 * MAXN];

void build(int id, int l, int r) {
    seg[id] = {1, 0};
    if(l == r)
        return;

    int mid = (l + r) >> 1;
    build(id << 1, l, mid);
    build(id << 1 | 1, mid + 1, r);
}

inline void pushDown(int id) {
    int &lz(seg[id].lz);
    for (int t = (id << 1); t <= (id << 1 | 1); ++t)
        seg[t] = {max(seg[t].maxv, lz), max(seg[t].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].maxv = max(seg[id].maxv, k);
        seg[id].lz = max(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].maxv = max(seg[id << 1].maxv, seg[id << 1 | 1].maxv);
}

int query(int id, int l, int r, int u, int v) {
    if(u <= l && r <= v)
        return seg[id].maxv;

    if(seg[id].lz)
        pushDown(id);

    int res(0), mid = (l + r) >> 1;
    if(mid >= u)
        res = query(id << 1, l, mid, u, v);

    if(mid + 1 <= v)
        res = max(res, query(id << 1 | 1, mid + 1, r, u, v));

    return res;
}

int sub3(int l, int r, int d) {
    for (int i = l; i <= r; ++i)
        B[i].clear();

    stack<int> st;
    for (int i = l; i <= r; ++i) {
        while(sz(st) && h[st.top()] - d < h[i])
            st.pop();

        prv[i] = (sz(st)) ? st.top() : l - 1;
        st.push(i);
    }

    while(sz(st))
        st.pop();

    for (int i = r; i >= l; --i) {
        while(sz(st) && h[st.top()] - d < h[i])
            st.pop();

        nxt[i] = (sz(st)) ? st.top() : r + 1;
        st.push(i);
    }

    vector<ii> sorted_h;
    for (int i = l; i <= r; ++i)
        sorted_h.push_back(ii(h[i], i));

    sort(sorted_h.begin(), sorted_h.end());

    int res(0), nTree(sz(sorted_h));
    build(1, 1, nTree);

    for (int i = l; i <= r; ++i) {
        for (int it = 0; it < sz(B[i]); ++it) {
            int j(B[i][it].fi), k(B[i][it].se);
            update(1, 1, nTree, 1, j, k);
        }

        int pos = upper_bound(sorted_h.begin(), sorted_h.end(), ii(h[i], 1e9)) - sorted_h.begin();
        int dpi = query(1, 1, nTree, pos, pos);
        //cout << i << ' ' << pos << ' ' << dpi << '\n';
        if(nxt[i] < r) {
            int pos = upper_bound(sorted_h.begin(), sorted_h.end(), ii(h[nxt[i]] - d, 1e9)) - sorted_h.begin();
            //cout << '.' << pos << '\n';
            B[nxt[i] + 1].push_back(ii(pos, 1 + dpi));
        }

        res = max(res, dpi);
    }

    return res;
}

int max_towers(int l, int r, int d) {
    ++l, ++r;
    if(check_sub1) {
        int res = 1 + (l < ksub1 && ksub1 < r && max(h[l], h[r]) <= h[ksub1] - d);
        return res;
    }

    return sub3(l, r, d);
    for (int i = l; i <= r; ++i)
        dp[i] = 1;

    for (int i = l; i <= r; ++i) {
        int k(i + 1);
        for (int j = i + 2; j <= r; ++j) {
            if(h[k] - d >= max(h[i], h[j]))
                dp[j] = max(dp[j], dp[i] + 1);

            if(h[j] > h[k])
                k = j;
        }
    }

    int res(0);
    for (int i = l; i <= r; ++i)
        res = max(res, dp[i]);

    //cout << sub3(l, r, d) << ' ';
    return res;
}

#ifdef Nhoksocqt1

int main(void) {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    #define TASK "towers"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    vector<int> _H;
    int _N, _Q;
    cin >> _N;

    _H.resize(_N);
    for (int i = 0; i < _N; ++i)
        cin >> _H[i];

    init(_N, _H);

    cin >> _Q;
    for (int t = 0; t < _Q; ++t) {
        int _L, _R, _D;
        cin >> _L >> _R >> _D;
        cout << "ANSWER FOR " << _L + 1 << ' ' << _R + 1 << ' ' << _D << ": " << max_towers(_L, _R, _D) << '\n';
    }

    return 0;
}

#endif // Nhoksocqt1

• 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