Submission #1151680

#	Time	Username	Problem	Language	Result	Execution time	Memory
1151680		QuantumK9	Village (BOI20_village)	C++17	100 / 100	50 ms	18748 KiB

Village

/*
 * @author Kian Chua
 * @date 01/2025
 *
*/

#include <bits/stdc++.h>

#define ll long long
#define pb push_back
#define mp make_pair
#define f first
#define s second

using namespace std;

int n;

vector<vector<int> > connect;
vector<bool> explored;
vector<int> parent;
priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > pq;

ll swaps_mx = 0;
vector<int> sz;
vector<int> preorder;

// returns depth of node (leaf nodes have depth=0)
int dfs(int i, int p) {
    explored[i] = true;
    parent[i] = p;
    preorder.pb(i);

    int sz_i = 1;
    int depth = -1;
    for (int j : connect[i]) {
        if (!explored[j]) {
            depth = max(depth, dfs(j, i));
            sz_i += sz[j];
        }
    }

    sz[i] = sz_i;
    swaps_mx += min(sz_i, n-sz_i);

    depth++;
    pq.push(mp(depth, i));

    return depth;
}

void solve() {
    cin >> n;
    connect.resize(n);
    parent.resize(n);
    explored.resize(n, false);

    sz.resize(n, 0);

    for (int i = 0; i < n-1; i++) {
        int a, b; cin >> a >> b; a--; b--;

        connect[a].pb(b);
        connect[b].pb(a);
    }

    dfs(0, -1);

    vector<int> smallest(n);
    for (int i = 0; i < n; i++) { smallest[i] = i+1; }

    int swaps = 0;
    while (!pq.empty()) {
        int cur = pq.top().s; pq.pop();

        if (!explored[cur]) { continue; }
        if (cur == 0) { // special handling
            swaps++;
            swap(smallest[cur], smallest[connect[cur][0]]);
            continue;
        }

        explored[cur] = false;
        explored[parent[cur]] = false;

        // swap with parent
        swaps++;
        swap(smallest[cur], smallest[parent[cur]]);
    }

    vector<int> largest(n);
    for (int i = 0; i < n; i++) { 
        largest[preorder[i]] = preorder[(i+(n/2))%n] + 1; 
    }

    cout << 2*swaps << " " << 2*swaps_mx << endl;
    for (int i : smallest) { cout << i << " "; } cout << endl;
    for (int i : largest) { cout << i << " "; } cout << endl;
    
    return;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int t = 1; //cin >> t;
    while(t--) { solve(); }
}

• Subtask 1: 12 / 12
• Subtask 2: 38 / 38
• Subtask 3: 50 / 50