Submission #1070655

#	Time	Username	Problem	Language	Result	Execution time	Memory
1070655		Boas	Radio Towers (IOI22_towers)	C++17	14 / 100	4054 ms	14344 KiB

towers

#include "towers.h"

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;

template <typename T1, typename T2>
using indexed_map = tree<T1, T2, less<T1>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T>
using indexed_set = indexed_map<T, null_type>;

#define loop(x, i) for (int i = 0; i < (x); i++)
#define loop1(x, i) for (int i = 1; i <= (x); i++)
#define rev(x, i) for (int i = (int)(x) - 1; i >= 0; i--)
#define itloop(x) for (auto it = begin(x); x != end(x); it++)
#define itrev(x) for (auto it = rbegin(x); x != rend(x); it++)
#define INF ((int64_t)(4e18 + 1))
#define INF32 ((int32_t)(2e9 + 1))
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
#define removeIn(x, l) l.erase(find(ALL(l), x))
#define pb push_back
#define sz(x) (int)(x).size()
#define F first
#define S second
#define var const auto &
#define foreach(l) for (var e : l)

typedef int8_t i8;
typedef int16_t i16;
typedef int32_t i32;
typedef int64_t i64;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<vii> vvii;
typedef vector<viii> vviii;
typedef set<int> si;
typedef set<ii> sii;
typedef set<iii> siii;
typedef vector<si> vsi;
typedef vector<sii> vsii;
typedef vector<vsi> vvsi;
typedef vector<string> vstr;
typedef vector<vector<string>> vvstr;
typedef vector<bool> vb;
typedef vector<vb> vvb;

vi h;
vii minTree, maxTree;
vi dp, maxDP;
vvi p;
int n;
int treeN = 1;
int lastD = -1;

void init(int N, vi H)
{
    h = H;
    n = N;
    while (treeN < N)
        treeN *= 2;
    minTree = vii(treeN * 2, {1e9, 1e9});
    maxTree = vii(treeN * 2, {0, -1e9});
    loop(n, i)
    {
        minTree[treeN + i] = {H[i], i};
        maxTree[treeN + i] = {H[i], -i};
    }
    rev(treeN, i)
    {
        minTree[i] = min(minTree[2 * i + 1], minTree[2 * i]);
        maxTree[i] = max(maxTree[2 * i + 1], maxTree[2 * i]);
    }
}

ii combine(ii a, ii b, bool minOp)
{
    if (minOp)
        return min(a, b);
    return max(a, b);
}

// v, ix
ii query(int i, int l, int r, int ql, int qr, bool minOp)
{
    if (r < ql || qr < l)
        return {1e9 * minOp, 1e9 * minOp};
    int m = l + (r - l) / 2;
    if (ql <= l && r <= qr)
    {
        if (minOp)
            return minTree[i];
        return maxTree[i];
    }
    return combine(query(2 * i, l, m, ql, qr, minOp),
                   query(2 * i + 1, m + 1, r, ql, qr, minOp), minOp);
}

void calcDP(int D)
{
    lastD = D;
    dp = maxDP = vi(n + 1, 1);
    p = vvi(20, vi(n + 1));
    for (int i = n - 2; i >= 0; i--)
    {
        int lo = i + 2, hi = n;
        bool suc = 0;
        int lastIx = -1;
        while (hi >= lo)
        {
            int m = lo + (hi - lo) / 2;
            if (i + 1 > m - 1)
            {
                lo = m + 1;
                continue;
            }
            auto [mn, mnIx] = query(1, 0, treeN - 1, i + 2, m, 1);
            auto [mx, mxIx] = query(1, 0, treeN - 1, i + 1, mnIx - 1, 0);
            mxIx *= -1;
            if (mx - max(mn, h[i]) >= D)
            {
                lastIx = mnIx;
                suc = 1;
                if (lo == hi)
                    break;
                hi = m;
            }
            else
            {
                lo = m + 1;
            }
        }
        if (suc)
        {
            p[0][i] = lastIx;
            dp[i] = maxDP[lastIx] + 1;
        }
        else
            p[0][i] = i;
        maxDP[i] = max(dp[i], maxDP[i + 1]);
    }
    loop1(19, x)
    {
        loop(n, i)
        {
            p[x][i] = p[x - 1][p[x - 1][i]];
        }
    }
}

int getParent(int i, int k)
{
    loop(20, x)
    {
        if ((1 << x) & k)
        {
            i = p[x][i];
        }
    }
    return i;
}

int max_towers(int L, int R, int D)
{
    if (lastD != D)
    {
        calcDP(D);
    }
    return max(maxDP[L] - maxDP[R - 1] + 1, 1);
}

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