Submission #714995

#	Time	Username	Problem	Language	Result	Execution time	Memory
714995		Stickfish	Swap (BOI16_swap)	C++17	100 / 100	422 ms	140164 KiB

swap

#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
using namespace std;

const int MAXN = 202020;
vector<vector<int>> dp[MAXN];
vector<int> subtr[MAXN];
int p[MAXN];

vector<int> unite_subtr(vector<int> ltr, vector<int> rtr) {
    auto lit = ltr.begin();
    auto rit = rtr.begin();
    vector<int> ans = {-1};
    for (int sz = 1; lit < ltr.end() || rit < rtr.end(); sz *= 2) {
        for (int i = 0; i < sz && lit + i < ltr.end(); ++i)
            ans.push_back(lit[i]);
        for (int i = 0; i < sz && rit + i < rtr.end(); ++i)
            ans.push_back(rit[i]);
        lit += sz;
        rit += sz;
    }
    return ans;
}

vector<int> merge(vector<int> a, vector<int> b) {
    auto bit = b.begin();
    vector<int> ans;
    for (auto ait = a.begin(); ait < a.end(); ++ait) {
        while (bit < b.end() && *bit < *ait) {
            ans.push_back(*(bit++));
        }
        ans.push_back(*ait);
    }
    while (bit < b.end()) {
        ans.push_back(*(bit++));
    }
    return ans;
}

vector<int> get_substit(vector<int> v, int pvl, int nvl) {
    vector<int> ans;
    for (auto x : v) {
        if (x == pvl)
            ans.push_back(nvl);
        else
            ans.push_back(x);
    }
    return ans;
}

vector<int> get_dp(int i, int t) {
    int lchd = i * 2 + 1;
    int rchd = i * 2 + 2;
    if (subtr[i].size() == 1)
        return {t};
    if (subtr[i].size() == 2)
        return {min(t, p[lchd]), max(t, p[lchd])};

    int ti = lower_bound(subtr[i].begin(), subtr[i].end(), t) - subtr[i].begin();
    assert(t < subtr[i][ti]);
    if (t != subtr[i][ti] - 1) {
        return get_substit(get_dp(i, subtr[i][ti] - 1), subtr[i][ti] - 1, t);
    }
    if (dp[i][ti].size()) {
        return dp[i][ti];
    }

    if (t < p[lchd] && t < p[rchd]) {
        dp[i][ti] = unite_subtr(get_dp(lchd, p[lchd]), get_dp(rchd, p[rchd]));
        dp[i][ti][0] = t;
        return dp[i][ti];
    }
    if (p[lchd] < t && p[lchd] < p[rchd]) {
        dp[i][ti] = unite_subtr(get_dp(lchd, t), get_dp(rchd, p[rchd]));
        dp[i][ti][0] = p[lchd];
        return dp[i][ti];
    }
    vector<int> dp0 = unite_subtr(get_dp(lchd, p[lchd]), get_dp(rchd, t));
    vector<int> dp1 = unite_subtr(get_dp(lchd, t), get_dp(rchd, p[lchd]));
    dp[i][ti] = min(dp0, dp1);
    dp[i][ti][0] = p[rchd];
    return dp[i][ti];
}

signed main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> p[i];
        --p[i];
    }
    for (int i = n - 1; i > 0; --i) {
        int rt = (i - 1) / 2;
        subtr[rt] = merge(subtr[rt], subtr[i]);
        subtr[rt] = merge(subtr[rt], {p[i]});
    }
    for (int i = 0; i < n; ++i) {
        subtr[i].push_back(n + 1);
        dp[i].resize(subtr[i].size());
    }
    for (auto x : get_dp(0, p[0])) {
        cout << x + 1 << ' ';
    }
    cout << endl;
}

• Subtask 1: 10 / 10
• Subtask 2: 11 / 11
• Subtask 3: 27 / 27
• Subtask 4: 20 / 20
• Subtask 5: 32 / 32