Submission #840167

#	Time	Username	Problem	Language	Result	Execution time	Memory
840167		socpite	Closing Time (IOI23_closing)	C++17	8 / 100	169 ms	47372 KiB

closing

#include "closing.h"

#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 5;
const long long INF = 1e18;

int onp[maxn];
long long depX[maxn], depY[maxn];
bool expanded[maxn];

vector<pair<int, int>> g[maxn];

void dfsX(int x, int p = -1)
{
    for (auto v : g[x])
    {
        if (v.first == p)
            continue;
        depX[v.first] = depX[x] + v.second;
        dfsX(v.first, x);
    }
}

void dfsY(int x, int p = -1)
{
    for (auto v : g[x])
    {
        if (v.first == p)
            continue;
        depY[v.first] = depY[x] + v.second;
        dfsY(v.first, x);
    }
}

long long solve1(int n, long long k)
{
    vector<long long> vec;
    vec.insert(vec.end(), depX, depX + n);
    vec.insert(vec.end(), depY, depY + n);
    sort(vec.begin(), vec.end());
    long long crr = 0;
    for (int i = 0; i < vec.size(); i++)
    {
        crr += vec[i];
        if (crr > k)
            return i;
    }
    return vec.size();
}

vector<int> path;

bool dfs_path(int x, int endp, int p = -1)
{
    if (x == endp)
        return (onp[x] = true);
    for (auto v : g[x])
    {
        if (v.first == p)
            continue;
        onp[x] |= dfs_path(v.first, endp, x);
    }
    return onp[x];
}

vector<long long> vec1, vec2;
vector<long long> knapsack[maxn];
int mark[maxn];

bool chk(pair<int, int> a)
{
    return a.second < mark[a.first];
}

long long tval(pair<int, int> a)
{
    if (chk(a))
        return knapsack[a.first][a.second];
    else
        return knapsack[a.first][a.second] + knapsack[a.first][a.second + 1];
}

long long eval(pair<int, int> a)
{
    if (chk(a))
        return knapsack[a.first][a.second] * 2;
    else
        return knapsack[a.first][a.second] + knapsack[a.first][a.second + 1];
}

struct cmp
{
    bool operator()(const pair<int, int> a, const pair<int, int> b) const
    {
        return eval(a) > eval(b);
    }
};

void expand(int id, priority_queue<pair<int, int>, vector<pair<int, int>>, cmp> &pq){
    assert(!expanded[id]);
    expanded[id] = 1;
    for (int i = mark[id]; i < knapsack[id].size(); i += 2)
        pq.push({id, i});
}

long long brute(priority_queue<pair<int, int>, vector<pair<int, int>>, cmp> pq, pair<int, int> val, long long k)
{
    auto old_pq = pq;
    long long ans1 = 0, ans2 = 0, old_k = k;
    while (!pq.empty())
    {
        auto x = pq.top();
        pq.pop();
        if (k >= tval(x))
            k -= tval(x);
        else
        {
            if (k >= knapsack[x.first][x.second])
                ans1++;
            break;
        }
        ans1 += 2;
    }
    pq = old_pq;
    k = old_k;
    if (k >= tval(val))
    {
        k -= tval(val);
        ans2++;
        assert(val.second+1 == mark[val.first]);
        expand(val.first, pq);
        while (!pq.empty())
        {
            auto x = pq.top();
            pq.pop();
            if (k >= tval(x))
                k -= tval(x);
            else
            {
                if (k >= knapsack[x.first][x.second])
                    ans2++;
                break;
            }
            ans2 += 2;
        }
    }
    return max(ans1, ans2) ;
}

void dfs_gen(int x, int p, long long cnst)
{
    long long val;
    if (p == -1)
        val = 0;
    else
        val = min(depX[x], depY[x]);
    if (val > cnst)
        vec2.push_back(val);
    else
        vec1.push_back(val);
    for (auto v : g[x])
    {
        if (v.first == p || onp[v.first])
            continue;
        dfs_gen(v.first, x, cnst);
    }
}


long long solve2(int n, long long k, int x, int y)
{
    dfs_path(x, y);
    int len = 0;
    for (int i = 0; i < n; i++)
    {
        if (onp[i])
        {
            k -= min(depX[i], depY[i]);
            vec1.clear();
            vec2.clear();
            long long inc = abs(depX[i] - depY[i]);
            dfs_gen(i, -1, inc);
            sort(vec1.begin(), vec1.end());
            sort(vec2.begin(), vec2.end());
            knapsack[len] = vec1;
            for (auto v : vec1)
                knapsack[len].push_back(inc);
            mark[len] = knapsack[len].size();
            for (auto v : vec2)
            {
                knapsack[len].push_back(v);
                knapsack[len].push_back(inc);
            }
            expanded[len] = 0;
            len++;
            // cout << i << endl;
            // for(auto v: knapsack[len])cout << v << " ";
            // cout << endl;
        }
    }
    // cout << "left " << k << endl;
    if (k < 0)
        return 0;
    long long re = 0;
    priority_queue<pair<int, int>, vector<pair<int, int>>, cmp> pq1;
    priority_queue<pair<int, int>, vector<pair<int, int>>, cmp> pq2;
    for (int i = 0; i < len; i++)
    {
        for (int j = 0; j < mark[i]; j++)
            pq1.push({i, j});
    }
    while (!pq1.empty() || !pq2.empty())
    {
        if (pq1.empty())
        {
            auto x = pq2.top();
            pq2.pop();
            if (k >= tval(x))
                k -= tval(x);
            else
            {
                if (k >= knapsack[x.first][x.second])
                {
                    re++;
                }
                break;
            }
            re += 2;
        }
        else if (pq2.empty())
        {
            auto x = pq1.top();
            pq1.pop();
            if (k >= tval(x))
            {
                k -= tval(x);
                if (x.second + 1 == mark[x.first])
                {
                    expand(x.first, pq2);
                }
            }
            else
                break;
            re++;
        }
        else
        {
            auto pval = pq2.top();
            pq2.pop();
            auto val1 = pq1.top();
            pq1.pop();
            if (pq1.empty())
            {
                pq2.push(pval);
                return re + brute(pq2, val1, k);
            }
            else
            {
                auto val2 = pq1.top();
                pq1.pop();
                if (tval(pval) < tval(val1) + tval(val2))
                {
                    if (k >= tval(pval))
                    {
                        pq1.push(val1);
                        pq1.push(val2);
                        k -= tval(pval);
                        re += 2;
                    }
                    else
                    {
                        pq2.push(pval);
                        return re + brute(pq2, val1, k);
                    }
                }
                else
                {
                    if (k >= tval(val1) + tval(val2))
                    {
                        if (val1.second + 1 == mark[val1.first])
                        {
                            expand(val1.first, pq2);
                        }
                        if (val2.second + 1 == mark[val2.first])
                        {
                            expand(val2.first, pq2);
                        }
                        pq2.push(pval);
                        k -= tval(val1);
                        k -= tval(val2);
                        re += 2;
                    }
                    else
                    {
                        pq2.push(pval);
                        return re + brute(pq2, val1, k);
                    }
                }
            }
        }
    }

    return re;
}

void reset(int n)
{
    for (int i = 0; i < n; i++)
    {
        g[i].clear();
        onp[i] = 0;
    }
    path.clear();
}

int max_score(int N, int X, int Y, long long K,
              std::vector<int> U, std::vector<int> V, std::vector<int> W)
{
    reset(N);
    for (int i = 0; i < N - 1; i++)
    {
        g[U[i]].push_back({V[i], W[i]});
        g[V[i]].push_back({U[i], W[i]});
    }
    depX[X] = 0;
    depY[Y] = 0;
    dfsX(X);
    dfsY(Y);
    long long ans = max(solve1(N, K), solve2(N, K, X, Y));
    return ans;
}

Compilation message (stderr)

closing.cpp: In function 'long long int solve1(int, long long int)':
closing.cpp:43:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |     for (int i = 0; i < vec.size(); i++)
      |                     ~~^~~~~~~~~~~~
closing.cpp: In function 'void expand(int, std::priority_queue<std::pair<int, int>, std::vector<std::pair<int, int> >, cmp>&)':
closing.cpp:103:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  103 |     for (int i = mark[id]; i < knapsack[id].size(); i += 2)
      |                            ~~^~~~~~~~~~~~~~~~~~~~~
closing.cpp: In function 'long long int solve2(int, long long int, int, int)':
closing.cpp:187:23: warning: unused variable 'v' [-Wunused-variable]
  187 |             for (auto v : vec1)
      |                       ^

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