Submission #866040

#	Time	Username	Problem	Language	Result	Execution time	Memory
866040		boris_mihov	Spring cleaning (CEOI20_cleaning)	C++17	100 / 100	162 ms	29804 KiB

cleaning

#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>
#include <queue>
#include <stack>

typedef long long llong;
const int MAXN = 200000 + 10;
const int MOD = 1e9 + 7;
const int INF = 2e9;

int n, q;
struct SegmentTree
{
    struct Node
    {
        int cntODD;
        int cntEVEN;
        bool lazy;

        Node()
        {
            cntODD = 0;
            cntEVEN = 0;
            lazy = false;
        }
    };

    Node tree[4*MAXN];
    Node combine(Node left, Node right)
    {
        Node res;
        res.cntODD = left.cntODD + right.cntODD;
        res.cntEVEN = left.cntEVEN + right.cntEVEN;
        return res;
    }

    void push(int node, int l, int r)
    {
        if (!tree[node].lazy)
        {
            return;
        }

        std::swap(tree[node].cntODD, tree[node].cntEVEN);
        if (l < r)
        {
            tree[2*node].lazy ^= 1;
            tree[2*node + 1].lazy ^= 1;
        }

        tree[node].lazy = false;
    }

    void build(int l, int r, int node, std::vector <int> &tour, bool par[])
    {
        if (l == r)
        {
            if (par[tour[l]]) tree[node].cntODD = 1;
            else tree[node].cntEVEN = 1;
            return;
        }

        int mid = (l + r) / 2;
        build(l, mid, 2*node, tour, par);
        build(mid + 1, r, 2*node + 1, tour, par);
        tree[node] = combine(tree[2*node], tree[2*node + 1]);
    }

    void update(int l, int r, int node, int queryL, int queryR)
    {
        push(node, l, r);
        if (r < queryL || queryR < l)
        {
            return;
        }

        if (queryL <= l && r <= queryR)
        {
            tree[node].lazy ^= 1;
            push(node, l, r);
            return;
        }

        int mid = (l + r) / 2;
        update(l, mid, 2*node, queryL, queryR);
        update(mid + 1, r, 2*node + 1, queryL, queryR);
        tree[node] = combine(tree[2*node], tree[2*node + 1]);
    }

    int count()
    {
        return tree[1].cntEVEN;
    }

    void build(std::vector <int> tour, bool par[])
    {
        assert(tour.size() == n);
        build(0, n - 1, 1, tour, par);
    }

    void update(int l, int r)
    {
        update(0, n - 1, 1, l, r);
    }
};

int cnt;
int par[MAXN];
bool res[MAXN];
bool was[MAXN];
SegmentTree tree;
bool isLeaf[MAXN];
std::vector <int> g[MAXN];
std::vector <int> tour;
int segPos[MAXN];
int heavy[MAXN];
int head[MAXN];
int sz[MAXN];

int dfs(int node, int p)
{
    par[node] = p;
    if (g[node].size() == 1)
    {
        cnt ^= 1;
        isLeaf[node] = true;
        res[node] = 1;
        return res[node];
    }

    res[node] = 0;
    for (const int &u : g[node])
    {
        if (u == p)
        {
            continue;
        }

        res[node] ^= dfs(u, node);
    }

    return res[node];
}

void initDFS(int node)
{
    sz[node] = 1;
    heavy[node] = 0;
    for (const int &u : g[node])
    {
        if (u == par[node])
        {
            continue;
        }

        initDFS(u);
        sz[node] += sz[u];
        if (sz[u] > sz[heavy[node]])
        {
            heavy[node] = u;
        }
    }
}

void buildTour(int node, int h)
{
    head[node] = h;
    tour.push_back(node);
    segPos[node] = tour.size() - 1;
    if (heavy[node] != 0)
    {
        buildTour(heavy[node], h);
    }

    for (const int &u : g[node])
    {
        if (u == par[node] || u == heavy[node])
        {
            continue;
        }

        buildTour(u, u);
    }
}

void climb(int node)
{
    tree.update(segPos[head[node]], segPos[node]);
    if (par[head[node]] != 0)
    {
        climb(par[head[node]]);
    } else
    {
        cnt ^= 1;
    }
}

int a[MAXN];
void solve()
{  
    int root = 1;
    if (g[1].size() == 1) root = g[1][0];
    dfs(root, 0);

    initDFS(root);
    buildTour(root, root);
    tree.build(tour, res);

    for (int i = 1 ; i <= q ; ++i)
    {
        int d;
        std::cin >> d;
        for (int j = 1 ; j <= d ; ++j)
        {
            std::cin >> a[j];
            if (isLeaf[a[j]] && !was[a[j]]) was[a[j]] = true;
            else 
            {
                climb(a[j]);
            }
        }

        if (cnt) std::cout << -1 << '\n';
        else std::cout << n + d + tree.count() - 2 << '\n';

        for (int j = 1 ; j <= d ; ++j)
        {
            if (isLeaf[a[j]] && was[a[j]]) was[a[j]] = false;
            else 
            {
                climb(a[j]);
            }
        }
    }
}   

void input()
{
    std::cin >> n >> q;
    for (int i = 2 ; i <= n ; ++i)
    {
        int u, v;
        std::cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
}

void fastIOI()
{
    std::ios_base :: sync_with_stdio(0);
    std::cout.tie(nullptr);
    std::cin.tie(nullptr);
}

int main()
{
    fastIOI();
    input();
    solve();

    return 0;
}

Compilation message (stderr)

In file included from /usr/include/c++/10/cassert:44,
                 from cleaning.cpp:4:
cleaning.cpp: In member function 'void SegmentTree::build(std::vector<int>, bool*)':
cleaning.cpp:100:28: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  100 |         assert(tour.size() == n);
      |                ~~~~~~~~~~~~^~~~

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 17 / 17
• Subtask 7: 30 / 30