Submission #878181

#	Time	Username	Problem	Language	Result	Execution time	Memory
878181		Alish	Spring cleaning (CEOI20_cleaning)	C++17	100 / 100	459 ms	23268 KiB

cleaning

#include <bits/stdc++.h>

using namespace std;

typedef long long int	ll;
typedef pair<int, int>	pii;
typedef pair<ll, ll>	pll;


#define F		        first
#define S		        second
#define pb		        push_back
#define endl            '\n'
#define Mp		        make_pair
#define all(x)          x.begin(), x.end()
#define debug(x)        cerr << #x << " = " << x << endl;
#define fast_io         ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io         freopen("in.txt" , "r+" , stdin) ; freopen("out.txt" , "w+" , stdout);


ll mod = 1e9+7 ;


const int N = 1e5+23;

vector<int> g[N];
int par[N], head[N], h[N], sz[N], bi[N], pos[N]; // hld
int seg[4*N], lpz[4*N], st[N], ft[N], tim;//segment
int deg[N];
int n, q;
int is[N];

void DFS(int v, int p=0){
    int Mx=0;
    sz[v]=1;
    for (int u: g[v]){
        if(u==p) continue;
        h[u]=h[v]+1;
        par[u]=v;
        DFS(u, v);
        if(sz[u]>Mx){
            bi[v]=u;
            Mx=sz[u];
        }
        sz[v]+=sz[u];
        is[v]+=is[u];
    }
}

void dfs(int v, int p=0){
    st[v]=tim;
    pos[st[v]]=v;
    tim++;
    if(!p) head[v]=v;
    if(bi[v]){
        head[bi[v]]=head[v];
        dfs(bi[v], v);
    }
    for (int u: g[v]){
        if(u==p || u==bi[v]) continue;
        head[u]=u;
        dfs(u, v);
    }
    ft[v]=tim;
}

void Shift(int l, int r, int ind){
    if(r-l==1) return;
    if(!lpz[ind]) return ;
    int mid=(r+l)>>1;
    seg[2*ind+1]=mid-l-seg[2*ind+1];
    seg[2*ind+2]=r-mid-seg[2*ind+2];
    lpz[2*ind+1]^=1;
    lpz[2*ind+2]^=1;
    lpz[ind]=0;
}
void build(int l=0, int r=n, int ind=0){
    if(r-l==1){
        if(is[pos[l]]%2==0) seg[ind]=1;
        return;
    }
    int mid=(r+l)>>1;
    build(l, mid, 2*ind+1); build(mid, r, 2*ind+2);
    seg[ind]=seg[2*ind+1]+seg[2*ind+2];
}

void upd(int lx, int rx, int l=0, int r=n, int ind=0){
    Shift(l, r, ind);
    if(lx>=r || rx<=l) return;
    if(lx<=l && rx>=r){
        seg[ind]=r-l-seg[ind];
        lpz[ind]^=1;
        return;
    }
    int mid=(r+l)>>1;
    upd(lx, rx, l, mid, 2*ind+1); upd(lx, rx, mid, r, 2*ind+2);
    seg[ind]=seg[2*ind+1]+seg[2*ind+2];
}

void updd(int v, int u){
    while(head[u]!=head[v]){
        if(h[head[u]] < h[head[v]]) swap(u, v);
        upd(st[head[u]], st[u]+1);
        u=par[head[u]];
    }
    if(h[v]>h[u]) swap(u, v);
    upd(st[v], st[u]+1);
}

int get(int i, int l=0, int r=n, int ind=0){
    Shift(l, r, ind);
    if(r-l==1) return seg[ind];
    int mid=(r+l)>>1;
    if(i<mid) return get(i, l, mid, 2*ind+1);
    return get(i, mid, r, 2*ind+2);
}


int main()
{
    fast_io
    cin>>n>>q;
    for (int i=0; i<n-1; i++){
        int u, v; cin>>v>>u;
        g[v].pb(u); g[u].pb(v);
        deg[v]++; deg[u]++;
    }
    int r=0;
    int leaf=0;
    for (int i=1; i<=n; i++){
        if(g[i].size()==1) is[i]=1;
        else r=i;
    }
    DFS(r); dfs(r);
    build();


    while(q--){
        vector<int> d;
        int k; cin>>k;
        for (int i=0; i<k; i++) {
            int p; cin>>p;
            d.pb(p);
        }
        for (auto pp: d) {
                if(deg[pp]==1) updd(r, pp);
                deg[pp]++;
        }
        for (auto pp: d) updd(r, pp);
        if(!get(0))cout<<-1<<endl;

        else cout<<n+k-1+seg[0]-1<<endl;
        for (auto pp: d) {
            deg[pp]--;
            if(deg[pp]==1)  updd(r, pp);
        }

        for (auto pp: d) updd(r, pp);
    }
}

Compilation message (stderr)

cleaning.cpp: In function 'int main()':
cleaning.cpp:129:9: warning: unused variable 'leaf' [-Wunused-variable]
  129 |     int leaf=0;
      |         ^~~~

• 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