Submission #1171426

#	Time	Username	Problem	Language	Result	Execution time	Memory
1171426		anmattroi	Closing Time (IOI23_closing)	C++17	83 / 100	406 ms	49372 KiB

closing

#include "closing.h"
#include <bits/stdc++.h>
#define maxn 200005
#define fi first
#define se second
using namespace std;
using ii = pair<int, int>;

int n, x, y; int64_t k;

int64_t disX[maxn], disY[maxn];

int64_t cost_level_one[maxn], cost_level_two[maxn];

vector<ii> adj[maxn];

void calcdisX() {

    function<void(int, int)> dfs = [&](int u, int dad) {
        for (auto [v, l] : adj[u])
        if (v != dad) {
            disX[v] = disX[u] + l;
            dfs(v, u);
        }
    };

    disX[x] = 0;
    dfs(x, -1);
}

void calcdisY() {

    function<void(int, int)> dfs = [&](int u, int dad) {
        for (auto [v, l] : adj[u])
        if (v != dad) {
            disY[v] = disY[u] + l;
            dfs(v, u);
        }
    };

    disY[y] = 0;
    dfs(y, -1);
}


int sub1() {
    vector<int64_t> nho;
    for (int i = 0; i < n; i++) nho.emplace_back(min(disX[i], disY[i]));
    sort(nho.begin(), nho.end());

    int64_t ans = 0;
    for (int i = 0; i < n; i++) {
        ans += nho[i];
        if (ans > k) return i;
    }
    return n;
}


int sub2() {
    int ans = 0;
    for (int i = 0; i < n; i++) {
        cost_level_one[i] = min(disX[i], disY[i]);
        cost_level_two[i] = max(disX[i], disY[i]) - cost_level_one[i];
    }

    int64_t sum = 0;


    multiset<ii> q1, q2, q3;

    for (int i = 0; i < n; i++)
        if (disX[i] + disY[i] == disX[y]) {
            ++ans;
            sum += cost_level_one[i];
            q1.insert({cost_level_two[i], i});
        } else {
            if (cost_level_one[i] > cost_level_two[i]) {
                q2.insert({cost_level_one[i] + cost_level_two[i], i});
                q3.insert({cost_level_one[i], i});
            } else {
                q1.insert({cost_level_one[i], i});
                q1.insert({cost_level_two[i], i});
            }
        }
    if (sum > k) return 0;


    while (1) {
        if (q1.empty() and q2.empty()) break;
        if (sum + (q1.empty() ? LLONG_MAX/2 : q1.begin()->fi) > k and
            sum + (q2.empty() ? LLONG_MAX/2 : q2.begin()->fi) > k) {
            if (sum + (q3.empty() ? LLONG_MAX/2 : q3.begin()->fi) > k) break;
            sum += q3.begin()->fi; break;
        }
        if (q1.size() >= 2 && !q2.empty()) {
            int s1 = q1.begin()->fi + next(q1.begin())->fi;
            if (s1 < q2.begin()->fi) {
                if (sum + q1.begin()->fi > k) {
                    if (sum + q3.begin()->fi <= k) {
                        sum += q3.begin()->fi;
                        ++ans;
                    }
                    break;
                }
                sum += q1.begin()->fi;
                ++ans;
                q1.erase(q1.begin());
                continue;
            }
            if (sum + q2.begin()->fi > k) {
                if (sum + q1.begin()->fi + q3.begin()->fi <= k) {
                    ans += 2;
                    break;
                } else if (sum + min(q1.begin()->fi, q3.begin()->fi) <= k) {
                    ++ans;
                    break;
                }
                break;
            }
            sum += q2.begin()->fi; ans += 2;
            q3.erase(ii{cost_level_one[q2.begin()->se], q2.begin()->se});
            q2.erase(q2.begin());
            continue;
        }
        if (q2.empty()) {
            if (sum + q1.begin()->fi > k) break;
            sum += q1.begin()->fi; ++ans;
            q1.erase(q1.begin());
            continue;
        }
        if (sum + q2.begin()->fi > k) {
            if (q1.empty()) {
                if (sum + q3.begin()->fi <= k) ++ans;
                break;
            }
            if (sum + q1.begin()->fi + q3.begin()->fi <= k) {
                ans += 2;
                break;
            } else if (sum + min(q1.begin()->fi, q3.begin()->fi) <= k) {
                ++ans;
                break;
            }
            break;
        }
        sum += q2.begin()->fi; ans += 2;
        q3.erase(ii{cost_level_one[q2.begin()->se], q2.begin()->se});
        q2.erase(q2.begin());
    }
    return ans;
}
/*
1
5 2 3 91
1 0 25
2 1 16
3 2 71
4 3 62
//34 + 49

4
*/

int max_score(int N, int X, int Y, long long K, vector<int> U, vector<int> V, vector<int> W) {
    n = N; x = X; y = Y; k = K;
    for (int i = 0; i < N-1; i++) {
        adj[U[i]].emplace_back(V[i], W[i]);
        adj[V[i]].emplace_back(U[i], W[i]);
    }
    calcdisX(); calcdisY();
    int ans = max(sub1(), sub2());
    for (int i = 0; i < N; i++) adj[i].clear();
    return ans;
}

/*
1
5 1 2 92
1 0 75
2 1 2
3 1 88
4 3 54
*/

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