Submission #261675

#	Time	Username	Problem	Language	Result	Execution time	Memory
261675		caoash	Swap (BOI16_swap)	C++17	48 / 100	1045 ms	68980 KiB

swap

#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")

#include <bits/stdc++.h> 
using namespace std;
 
using ll = long long;
 
using vi = vector<int>;
#define pb push_back
#define rsz resize
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
 
using pi = pair<int,int>;
#define f first
#define s second
#define mp make_pair
 
const int MX = 200005;
 
int n; int num[MX]; map<pi, vi> dp; 
 
void merge(vi &best, vi a, int x, vi b) {
    vi ret;
    ret.pb(x);
    int p1 = 0, p2 = 0;
    for (int i = 0; i < 36; i++) {
        if (p1 < sz(a)) {
            for (int j = 0; j < (1 << i); j++) {
                if (p1 < sz(a)) {
                    ret.pb(a[p1++]);
                }
                else {
                    break;
                }
            } 
        }
        if (p2 < sz(b)) {
            for (int j = 0; j < (1 << i); j++) {
                if (p2 < sz(b)) {
                    ret.pb(b[p2++]);
                } 
                else {
                    break;
                }
            }
        }
    }
    if (best.empty()) best = ret;
    else best = min(best, ret);
}

vi solve(int v, int c) {
    if (!dp[mp(v, c)].empty()) {
        return dp[mp(v, c)];
    }
    int l = 2 * v + 1, r = 2 * v + 2;
    if (l >= n) {
        return dp[mp(v, c)] = {c};
    }
    if (r >= n) {
        vi best; 
        vi fst = solve(l, num[l]);
        best.pb(c);
        for (int x : fst) best.pb(x);
        vi sec = solve(l, c);
        vi sbest;
        sbest.pb(num[l]);
        for (int x : sec) sbest.pb(x);
        return dp[mp(v, c)] = min(best, sbest);
    }
    vi best;
    // no swaps
    merge(best, solve(l, num[l]), c, solve(r, num[r]));
 
    // swap left
    if (l < n) {
        merge(best, solve(l, c), num[l], solve(r, num[r]));
    }
 
    // swap right
    if (r < n) {
        merge(best, solve(l, num[l]), num[r], solve(r, c));
    }
 
    // swap left, then right
    if (r < n) {
        merge(best, solve(l, c), num[r], solve(r, num[l]));
    }
    return dp[mp(v, c)] = best;
}
 
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> num[i];
    }
    solve(0, num[0]); 
    vi ans = dp[mp(0, num[0])];
    for (int i = 0; i < n; i++) {
        cout << ans[i] << ' ';
    }
    cout << '\n';
}

Compilation message (stderr)

swap.cpp:2:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("O3")
 
swap.cpp:3:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("unroll-loops")

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