Submission #841800

#	Time	Username	Problem	Language	Result	Execution time	Memory
841800		grt	Closing Time (IOI23_closing)	C++17	43 / 100	121 ms	33744 KiB

closing

//GRT_2018
#include <bits/stdc++.h>
#define PB push_back
#define ST first
#define ND second
#define all(x) x.begin(), x.end()
//mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

using namespace std;

using ll = long long;
using pi = pair<int,int>;
using vi = vector<int>;

const int nax = 200 * 1000 + 10;
int n, endX, endY;
vector<pi> V[nax];
pair<ll,ll> dist[nax];

void dfs(int x, int par, int bit) {
    for (auto [y, w] : V[x]) {
        if (y == par) continue;
        if (bit == 0) dist[y].ST = dist[x].ST + w;
        else dist[y].ND = dist[x].ND + w;
        dfs(y, x, bit);
    }
}

int max_score(int N, int x, int y, ll k, vi u, vi v, vi w) {
    n = N;
    endX = x;
    endY = y;
    for (int i = 0; i < n; ++i) {
        V[i].clear();
    }
    for (int i = 0; i < n - 1; ++i) {
        V[u[i]].emplace_back(v[i], w[i]);
        V[v[i]].emplace_back(u[i], w[i]);
    }
    dist[endX].ST = 0;
    dfs(endX, -1, 0);
    dist[endY].ND = 0;
    dfs(endY, -1, 1);
    ll d = dist[endY].ST;


    for (int i = 0; i < n; ++i) {
        if (dist[i].ST > dist[i].ND) {
            swap(dist[i].ST, dist[i].ND);
        }
    }
    sort(dist, dist + n);

    int ans = 0;
    ll s = 0;
    for (int i = 0; i < n; ++i) {
        s += dist[i].ST;
        if (s <= k) ans = max(ans, i + 1);
        swap(dist[i].ST, dist[i].ND);
    }
    sort(dist, dist + n);
    int cur = 0;
    multiset<ll>ext;

    for (int i = 0; i < n; ++i) {
        if (dist[i].ST + dist[i].ND == d) {
            cur++;
            k -= dist[i].ND;
        } else {
            ext.insert(dist[i].ND);
        }
    }
    if (k < 0) return ans;

    s = 0;
    for (int i = 0; i < n; ++i) {
        if (dist[i].ST + dist[i].ND == d) {
            s += dist[i].ST - dist[i].ND;
            cur++;
        } else {
            s += dist[i].ST;
            cur += 2;
            ext.erase(ext.find(dist[i].ND));
        }
        ll s2 = 0;
        int add = 0;
        for (auto it : ext) {
            if (s + s2 + it <= k) {
                add++;
                s2 += it;
            } else {
                break;
            }
        }
        if (s <= k) {
            ans = max(ans, cur + add);
        }
    }

    return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 9 / 9
• Subtask 3: 12 / 12
• Subtask 4: 14 / 14
• Subtask 5: 0 / 9
• Subtask 6: 0 / 11
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17