Submission #1305176

#	Time	Username	Problem	Language	Result	Execution time	Memory
1305176		red_souls	Spring cleaning (CEOI20_cleaning)	C++20	100 / 100	121 ms	19048 KiB

cleaning

#include <bits/stdc++.h>
#define ll long long
#define task "SPRINGCLEANING"
using namespace std;

const int N = 1e5 + 16;
int n, q, u, v;
vector <int> adj[N];

namespace sub7 {

    int leaves[N];

    void dpCalc(int k, int p) {
        if (k != 1 && adj[k].size() == 1) {
            leaves[k] = 1;
        }
        for (auto v : adj[k]) {
            if (v == p) {
                continue;
            }
            dpCalc(v, k);
            leaves[k] += leaves[v];
        }
        if (leaves[k] & 1) {
            leaves[k] = 1;
        }
        else {
            leaves[k] = 2;
        }
    }

    int sz[N], h[N], par[N];
    int chainHead[N], chainArr[N], chainId[N], pos[N], curPos = 1, curChain = 1;

    void dfs(int k, int p) {
        sz[k] = 1;
        for (auto v : adj[k]) {
            if (v == p) {
                continue;
            }
            h[v] = h[k] + 1;
            par[v] = k;
            dfs(v, k);
            sz[k] += sz[v];
        }
    }

    void hld(int k, int p) {
        if (!chainHead[curChain]) {
            chainHead[curChain] = k;
        }
        chainId[k] = curChain;
        pos[k] = curPos;
        chainArr[curPos] = k;
        curPos++;
        int heaviest = 0;
        for (auto v : adj[k]) {
            if (v == p) {
                continue;
            }
            if (heaviest == 0 || sz[v] > sz[heaviest]) {
                heaviest = v;
            }
        }
        if (heaviest) {
            hld(heaviest, k);
        }
        for (auto v : adj[k]) {
            if (v == p || v == heaviest) {
                continue;
            }
            curChain++;
            hld(v, k);
        }
    }

    int lca(int u, int v) {
        while (chainId[u] != chainId[v]) {
            if (chainId[u] > chainId[v]) {
                u = par[chainHead[chainId[u]]];
            }
            else {
                v = par[chainHead[chainId[v]]];
            }
        }
        if (h[u] < h[v]) {
            return u;
        }
        return v;
    }

    struct node {
        int val = 0, lazy = 0;

        node operator + (const node &other) const {
            node ans;
            ans.val = val + other.val;
            return ans;
        }
    };

    node segmentTree[N << 2];

    void build(int k, int l, int r) {
        if (l == r) {
            segmentTree[k].val = (leaves[chainArr[l]] == 2 ? 1 : 0);
            return;
        }
        int mid = l + r >> 1;
        build(k << 1, l, mid);
        build(k << 1 | 1, mid + 1, r);
        segmentTree[k] = segmentTree[k << 1] + segmentTree[k << 1 | 1];
    }

    void down(int k, int l, int r) {
        if (segmentTree[k].lazy) {

            int mid = l + r >> 1;

            segmentTree[k << 1].val = (mid - l + 1) - segmentTree[k << 1].val;
            segmentTree[k << 1].lazy ^= 1;

            segmentTree[k << 1 | 1].val = (r - mid) - segmentTree[k << 1 | 1].val;
            segmentTree[k << 1 | 1].lazy ^= 1;

            segmentTree[k].lazy = 0;
        }
    }

    void update(int k, int l, int r, int x, int y) {
        if (l > y || x > r) {
            return;
        }
        if (l >= x && r <= y) {
            segmentTree[k].val = (r - l + 1) - segmentTree[k].val;
            segmentTree[k].lazy ^= 1;
            return;
        }
        int mid = l + r >> 1;
        down(k, l, r);
        update(k << 1, l, mid, x, y);
        update(k << 1 | 1, mid + 1, r, x, y);
        segmentTree[k] = segmentTree[k << 1] + segmentTree[k << 1 | 1];
    }

    void updateTree(int u, int v) {
        int LCA = lca(u, v);
        while (chainId[u] != chainId[LCA]) {
            update(1, 1, curPos, pos[chainHead[chainId[u]]], pos[u]);
            u = par[chainHead[chainId[u]]];
        }
        while (chainId[v] != chainId[LCA]) {
            update(1, 1, curPos, pos[chainHead[chainId[v]]], pos[v]);
            v = par[chainHead[chainId[v]]];
        }
        if (h[u] < h[v]) {
            update(1, 1, curPos, pos[u] + 1, pos[v]);
        }
        else {
            update(1, 1, curPos, pos[v] + 1, pos[u]);
        }
    }

    int a[N], cntLeaves, isLeaf[N], deg[N], bonus[N];

    void solve() {
        dpCalc(1, 1);
        leaves[1] = 0;
        dfs(1, 1);
        hld(1, 1);
        build(1, 1, curPos);

        for (int i = 1; i <= n; i++) {
            if (adj[i].size() == 1) {
                cntLeaves++;
                isLeaf[i] = true;
            }
            deg[i] = adj[i].size();
        }

        for (int z = 1; z <= q; z++) {
            int D;
            cin >> D;
            for (int i = 1; i <= D; i++) {
                cin >> a[i];
            }

            vector <int> lst;
            int cnt = cntLeaves;
            for (int i = 1; i <= D; i++) {
                if (deg[a[i]] == 1) {
                    cnt--;
                }
                deg[a[i]]++;
                bonus[a[i]]++;
                cnt++;
                lst.push_back(a[i]);
            }
            sort(lst.begin(), lst.end());
            lst.erase(unique(lst.begin(), lst.end()), lst.end());

            if (cnt & 1) {
                cout << -1 << "\n";
                for (auto x : lst) {
                    deg[x] = adj[x].size();
                    bonus[x] = 0;
                }
                continue;
            }

            for (auto x : lst) {
                if (isLeaf[x] && (bonus[x] & 1) == 0) {
                    updateTree(1, x);
                }
                if (!isLeaf[x] && (bonus[x] & 1) == 1) {
                    updateTree(1, x);
                }
            }

            cout << n + D - 1 + segmentTree[1].val << "\n";

            for (auto x : lst) {
                if (isLeaf[x] && (bonus[x] & 1) == 0) {
                    updateTree(1, x);
                }
                if (!isLeaf[x] && (bonus[x] & 1) == 1) {
                    updateTree(1, x);
                }
            }

            for (auto x : lst) {
                deg[x] = adj[x].size();
                bonus[x] = 0;
            }
        }
    }
}

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

    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }

    cin >> n >> q;
    for (int i = 1; i < n; i++) {
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    sub7 :: solve();

    return 0;
}

Compilation message (stderr)

cleaning.cpp: In function 'int main()':
cleaning.cpp:246:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  246 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
cleaning.cpp:247:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  247 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• 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