Submission #1282923

#	Time	Username	Problem	Language	Result	Execution time	Memory
1282923		TVSown	Spring cleaning (CEOI20_cleaning)	C++20	100 / 100	171 ms	20684 KiB

cleaning

///*** Sown_Vipro ***///
/// ->TEAM SELECTION TEST<- ///

#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("popcnt")
#define F first
#define S second
#define pb push_back
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
#define REP(i, a, b) for(int i = a; i >= b; --i)
#define all(s) s.begin(), s.end()
#define szz(s) int(s.size())
const string NAME = "sown";
const int N = 1e6 + 5, MAX = 1e6, MOD = 1e9 + 7;
void maxi(int &x, int y){ if(x < y) x = y; }
void mini(int &x, int y){ if(x > y) x = y; };
void add(int &x, int y){ x += y; x += MOD * (x < 0); x -= MOD * (x >= MOD); };
int n, q, res, TIME, stt;
int s[N], c[N], nxt[N], ver[N], chain[N], p[N], in[N], cc[N], icon[N], a[N], d[N], check[N];
vector<int> e[N];

void pre(int u){
    s[u] = 1;
    c[u] = (e[u].size() == 1);
    for(int v : e[u]){
        if(v == p[u]) continue;
        p[v] = u;
        pre(v);
        s[u] += s[v];
        if(s[v] > s[nxt[u]]) nxt[u] = v;
        c[u] += c[v];
    }
}

pi st[4 * N];
int lz[4 * N];

pi Merge(pi A, pi B){
    return {A.F + B.F, A.S + B.S};
}

void build(int id, int l, int r){
    if(l == r){
        if(ver[l] != 1){
//            cout << ver[l] << " " << c[ver[l]] << "\n";
            st[id].F = (c[ver[l]] % 2 == 0);
            st[id].S = (c[ver[l]] % 2 != 0);
        }
        return;
    }
    int m = (l + r) / 2;
    build(2 * id, l, m);
    build(2 * id + 1, m + 1, r);
    st[id] = Merge(st[2 * id], st[2 * id + 1]);
}

void down(int id){
    if(lz[id]){
        swap(st[2 * id].F, st[2 * id].S);
        swap(st[2 * id + 1].F, st[2 * id + 1].S);
        lz[2 * id] ^= 1;
        lz[2 * id + 1] ^= 1;
        lz[id] = 0;
    }
}

void update(int id, int l, int r, int u, int v){
    if(l > v || r < u) return;

    if(u <= l && r <= v){
        swap(st[id].F, st[id].S);
        lz[id] ^= 1;
//        cout << l << " " << r << " " << st[id].F << " " << st[id].S << "\n";
        return;
    }
    down(id);
    int m = (l + r) / 2;
    update(2 * id, l, m, u, v);
    update(2 * id + 1, m + 1, r, u, v);
    st[id] = Merge(st[2 * id], st[2 * id + 1]);
}

void hld(int u, int p){
    if(!icon[stt]) icon[stt] = u;
    chain[u] = stt;
    in[u] = ++TIME;
    ver[TIME] = u;

    if(nxt[u]) hld(nxt[u], u);

    for(int v : e[u]){
        if(v != p && v != nxt[u]){
            ++stt;
            hld(v, u);
        }
    }
}

void solve(){
    cin >> n >> q;
    FOR(i, 2, n){
        int u, v; cin >> u >> v;
        e[u].pb(v);
        e[v].pb(u);
    }

    pre(1);
    hld(1, 0);
    build(1, 1, n);

//    cout << st[1].F;

    while(q--){
        int s; cin >> s;
        int leaves = 0;
        FOR(i, 1, s){
            cin >> a[i];
            if(cc[a[i]] == 0){
                cc[a[i]] = 1;
                leaves += (e[a[i]].size() == 1);
            }
            ++d[a[i]];
        }

//        cout << c[1] << " " << s << " " << leaves << "\n";
        if((c[1] + s - leaves) % 2){
            cout << -1 << "\n";
            FOR(i, 1, s){
                --d[a[i]];
                cc[a[i]] = 0;
            }
            continue;
        }

        FOR(i, 1, s){
            if((d[a[i]] - (e[a[i]].size() == 1)) % 2 && check[a[i]] == 0){
                check[a[i]] = 1;
                int u = a[i];
//                cout << u << "\n";
                while(chain[u] != chain[1]){
                    update(1, 1, n, in[icon[chain[u]]], in[u]);
    //                cout << icon[chain[u]] << " " << u << "\n";
                    u = p[icon[chain[u]]];
                }
                update(1, 1, n, 1, in[u]);
            }
        }
        cout << n + s - 1 + st[1].F << "\n";
        FOR(i, 1, s){
            if((d[a[i]] - (e[a[i]].size() == 1)) % 2 && check[a[i]] == 1){
                check[a[i]] = 0;
                int u = a[i];
                while(chain[u] != chain[1]){
                    update(1, 1, n, in[icon[chain[u]]], in[u]);
    //                cout << icon[chain[u]] << " " << u << "\n";
                    u = p[icon[chain[u]]];
                }
                update(1, 1, n, 1, in[u]);
            }
        }
        FOR(i, 1, s){
            --d[a[i]];
            cc[a[i]] = 0;
        }
    }
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    if(fopen((NAME + ".inp").c_str(), "r")){
        freopen((NAME + ".inp").c_str(), "r", stdin);
//        freopen((NAME + ".out").c_str(), "w", stdout);
    }
    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

cleaning.cpp: In function 'int main()':
cleaning.cpp:177:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  177 |         freopen((NAME + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• 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