Submission #741446

#	Time	Username	Problem	Language	Result	Execution time	Memory
741446		GrindMachine	Swap (BOI16_swap)	C++17	68 / 100	545 ms	262144 KiB

swap

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
https://usaco.guide/problems/baltic-oi-2016swap/solution
hidden tcs

*/

const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<int> merge(int root, vector<int> v1, vector<int> v2) {
    vector<int> v3;
    v3.pb(root);

    int curr = 1;
    int ptr = 0;

    while (ptr < sz(v1) or ptr < sz(v2)) {
        rep(j, curr) {
            if (ptr < sz(v1)) {
                v3.pb(v1[ptr]);
            }
            ptr++;
        }

        ptr -= curr;

        rep(j, curr) {
            if (ptr < sz(v2)) {
                v3.pb(v2[ptr]);
            }
            ptr++;
        }

        curr *= 2;
    }

    return v3;
}

vector<int> a(N * 2, inf1);
int n;
Tree<int> states[N];

void gen_states(int i, int j) {
    if (i > n) return;
    if (states[i].find(j) != states[i].end()) return;

    states[i].insert(j);

    int l = 2 * i, r = 2 * i + 1;

    if (j < a[l] and j < a[r]) {
        gen_states(l, a[l]);
        gen_states(r, a[r]);
    }
    else if (a[l] < j and a[l] < a[r]) {
        states[i].insert(a[l]);
        gen_states(l, j);
        gen_states(r, a[r]);
    }
    else {
        states[i].insert(a[r]);
        gen_states(l, a[l]);
        gen_states(r, j);
        gen_states(l, j);
        gen_states(r, a[l]);
    }
}

void solve(int test_case)
{
    cin >> n;
    rep1(i, n) cin >> a[i];

    gen_states(1, a[1]);

    vector<vector<int>> dp[n + 5];

    rev(i, n, 1) {
        int siz = sz(states[i]);
        dp[i] = vector<vector<int>>(siz);

        int ind1 = -1, ind2 = -1, ind3 = -1;
        int l = 2 * i, r = 2 * i + 1;

        trav(j, states[i]) {
            ind1++;

            if (l > n and r > n) {
                dp[i][ind1] = {j};
            }
            else if (r > n) {
                dp[i][ind1] = {min(j, a[l]), max(j, a[l])};
            }
            else {
                if (j < a[l] and j < a[r]) {
                    // no swap
                    ind2 = states[l].order_of_key(a[l]);
                    ind3 = states[r].order_of_key(a[r]);
                    dp[i][ind1] = merge(j, dp[l][ind2], dp[r][ind3]);
                }
                else if (a[l] < j and a[l] < a[r]) {
                    // swap with left
                    ind2 = states[l].order_of_key(j);
                    ind3 = states[r].order_of_key(a[r]);
                    dp[i][ind1] = merge(a[l], dp[l][ind2], dp[r][ind3]);
                }
                else {
                    // swap with right
                    ind2 = states[l].order_of_key(a[l]);
                    ind3 = states[r].order_of_key(j);
                    dp[i][ind1] = merge(a[r], dp[l][ind2], dp[r][ind3]);

                    // swap with left and swap with right
                    ind2 = states[l].order_of_key(j);
                    ind3 = states[r].order_of_key(a[l]);
                    amin(dp[i][ind1], merge(a[r], dp[l][ind2], dp[r][ind3]));
                }
            }
        }

        if (l <= n) {
            vector<vector<int>>().swap(dp[l]);
            // dp[l].clear();
            // dp[l].shrink_to_fit();
        }

        if (r <= n) {
            vector<vector<int>>().swap(dp[r]);
            // dp[r].clear();
            // dp[r].shrink_to_fit();
        }
    }

    int ind = states[1].order_of_key(a[1]);
    auto ans = dp[1][ind];

    trav(x, ans) cout << x << " ";
    cout << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message (stderr)

swap.cpp: In function 'std::vector<int> merge(int, std::vector<int>, std::vector<int>)':
swap.cpp:71:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |     while (ptr < sz(v1) or ptr < sz(v2)) {
      |                ^
swap.cpp:71:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |     while (ptr < sz(v1) or ptr < sz(v2)) {
      |                                ^
swap.cpp:73:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |             if (ptr < sz(v1)) {
      |                     ^
swap.cpp:82:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   82 |             if (ptr < sz(v2)) {
      |                     ^

• Subtask 1: 10 / 10
• Subtask 2: 11 / 11
• Subtask 3: 27 / 27
• Subtask 4: 20 / 20
• Subtask 5: 0 / 32