Submission #1179514

#	Time	Username	Problem	Language	Result	Execution time	Memory
1179514		gyg	송신탑 (IOI22_towers)	C++20	11 / 100	4069 ms	3304 KiB

towers

#include "towers.h"
#include <bits/stdc++.h>
using namespace std;
#define arr array 
#define vec vector
const int N = 1e5 + 5;

int n;
arr<int, N> h;

void init(int _n, vec<int> _h) {
    n = _n;
    for (int i = 1; i <= n; i++) h[i] = _h[i - 1];
}

int s, f, d;

struct Sgt {
    arr<int, 4 * N> tr;
    void intl() {
        tr.fill(0);
    }
    void upd(int i, int x) {
        tr[i] = x;
    }
    int qry(int l, int r) {
        int ans = 0;
        for (int i = l; i <= r; i++) ans = max(ans, tr[i]);
        return ans;
    }
} sgt;

arr<int, N> lf, rg;
void prp_cmp() {
    sgt.intl();
    for (int i = 1; i <= n; i++) sgt.upd(i, h[i]);

    for (int i = 1; i <= n; i++) {
        int lw = 1, hg = i;
        while (lw < hg) {
            int md = (lw + hg + 1) / 2;
            if (sgt.qry(md, i) >= h[i] + d) lw = md;
            else hg = md - 1;
        }
        lf[i] = (sgt.qry(lw, i) >= h[i] + d) ? lw : 1;

        lw = i, hg = n;
        while (lw < hg) {
            int md = (lw + hg) / 2;
            if (sgt.qry(i, md) >= h[i] + d) hg = md;
            else lw = md + 1;
        }
        rg[i] = (sgt.qry(i, lw) >= h[i] + d) ? lw : n;
    }

    // for (int i = 1; i <= n; i++) {
    //     cout << i << ": " << lf[i] << " " << rg[i] << '\n';
    // }
}

arr<int, N> dp;
void dp_cmp() {
    for (int i = s; i <= f; i++) {
        dp[i] = 1;
        for (int j = s; j <= i - 1; j++) {
            if (j < lf[i] && i > rg[j]) {
                dp[i] = max(dp[i], dp[j] + 1);
            }
        }
    }
}

int max_towers(int _s, int _f, int _d) {
    s = _s + 1, f = _f + 1, d = _d;

    prp_cmp();
    dp_cmp();

    int ans = 0;
    for (int i = s; i <= f; i++) ans = max(ans, dp[i]);
    return ans;
}

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