結果

問題 No.3442 Good Vertex Connectivity
コンテスト
ユーザー 👑 potato167
提出日時 2026-01-04 16:32:28
言語 C++17
(gcc 15.2.0 + boost 1.89.0)
結果
AC  
実行時間 1,142 ms / 3,000 ms
コード長 6,161 bytes
記録
記録タグの例:
初AC ショートコード 純ショートコード 純主流ショートコード 最速実行時間
コンパイル時間 2,430 ms
コンパイル使用メモリ 228,116 KB
実行使用メモリ 49,128 KB
最終ジャッジ日時 2026-02-06 20:52:41
合計ジャッジ時間 41,042 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 69
権限があれば一括ダウンロードができます

ソースコード

diff #
raw source code 

#include <bits/stdc++.h>
using namespace std;

struct NodeAgg {
    int cnt = 0;
    int first = -1;  // vertex id
    int last = -1;   // vertex id
    long long sum = 0; // sum of dist between consecutive active nodes in-order (linear)
};

static const int MAXLOG = 20;

int N;
vector<vector<int>> g;
vector<int> depthv;
int up[MAXLOG][200000 + 5];
int tin[200000 + 5], tout[200000 + 5], euler[200000 + 5];
int timer_ = 0;

bool is_ancestor(int a, int b){
    // a is ancestor of b in rooted tree
    return tin[a] <= tin[b] && tout[b] <= tout[a];
}

int jump_up(int v, int k){
    for(int j=0;j<MAXLOG;j++){
        if(k & (1<<j)) v = up[j][v];
    }
    return v;
}

int lca(int a, int b){
    if(is_ancestor(a,b)) return a;
    if(is_ancestor(b,a)) return b;
    int v = a;
    for(int j=MAXLOG-1;j>=0;j--){
        int nv = up[j][v];
        if(nv != 0 && !is_ancestor(nv, b)) v = nv;
    }
    return up[0][v];
}

long long dist_uv(int a, int b){
    int c = lca(a,b);
    return (long long)depthv[a] + depthv[b] - 2LL*depthv[c];
}

struct SegTree {
    int n;              // size (power of two)
    vector<NodeAgg> st; // 1-indexed internal or 0-indexed iterative

    static NodeAgg mergeAgg(const NodeAgg &L, const NodeAgg &R){
        if(L.cnt == 0) return R;
        if(R.cnt == 0) return L;
        NodeAgg res;
        res.cnt = L.cnt + R.cnt;
        res.first = L.first;
        res.last = R.last;
        res.sum = L.sum + R.sum + dist_uv(L.last, R.first);
        return res;
    }

    SegTree(int sz=0){ init(sz); }

    void init(int sz){
        n = 1;
        while(n < sz) n <<= 1;
        st.assign(2*n, NodeAgg());
    }

    void build_from_active(const vector<int> &active_by_tin){
        // active_by_tin is size N+1 (1..N), position = tin vertex
        for(int i=0;i<N;i++){
            int v = euler[i]; // vertex at position i
            NodeAgg leaf;
            if(active_by_tin[v]){
                leaf.cnt = 1;
                leaf.first = leaf.last = v;
                leaf.sum = 0;
            }
            st[n+i] = leaf;
        }
        for(int i=n-1;i>=1;i--){
            st[i] = mergeAgg(st[i<<1], st[i<<1|1]);
        }
    }

    void update_pos(int pos0, int vertex_or_minus1){
        // pos0: 0-indexed position in euler order
        NodeAgg leaf;
        if(vertex_or_minus1 != -1){
            leaf.cnt = 1;
            leaf.first = leaf.last = vertex_or_minus1;
            leaf.sum = 0;
        }
        int i = n + pos0;
        st[i] = leaf;
        for(i >>= 1; i >= 1; i >>= 1){
            st[i] = mergeAgg(st[i<<1], st[i<<1|1]);
            if(i==1) break;
        }
    }

    NodeAgg query_range(int l, int r){
        // [l, r) 0-indexed, order-sensitive
        NodeAgg leftAcc, rightAcc;
        for(l += n, r += n; l < r; l >>= 1, r >>= 1){
            if(l & 1) leftAcc = mergeAgg(leftAcc, st[l++]);
            if(r & 1) rightAcc = mergeAgg(st[--r], rightAcc);
        }
        return mergeAgg(leftAcc, rightAcc);
    }
};

long long steiner_vertices_from_agg(const NodeAgg &agg){
    if(agg.cnt == 0) return 0;
    if(agg.cnt == 1) return 1;
    long long cycle = agg.sum + dist_uv(agg.last, agg.first);
    long long edges = cycle / 2;
    return edges + 1;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N;
    g.assign(N+1, {});
    for(int i=0;i<N-1;i++){
        int a,b; cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    vector<int> color(N+1);
    for(int i=1;i<=N;i++) cin >> color[i];

    depthv.assign(N+1, 0);

    // DFS iterative to fill tin/tout, up[0], depth, euler array
    // root at 1, parent of root = 0
    vector<int> parent(N+1,0);
    vector<int> it(N+1,0);
    vector<int> stv;
    stv.reserve(N);
    stv.push_back(1);
    parent[1]=0;
    up[0][1]=0;
    depthv[1]=0;

    while(!stv.empty()){
        int v = stv.back();
        if(it[v]==0){
            tin[v]=timer_;
            euler[timer_] = v;
            timer_++;
        }
        if(it[v] < (int)g[v].size()){
            int to = g[v][it[v]++];
            if(to==parent[v]) continue;
            parent[to]=v;
            up[0][to]=v;
            depthv[to]=depthv[v]+1;
            stv.push_back(to);
        }else{
            tout[v]=timer_-1;
            stv.pop_back();
        }
    }

    for(int j=1;j<MAXLOG;j++){
        for(int v=1;v<=N;v++){
            int mid = up[j-1][v];
            up[j][v] = (mid==0?0:up[j-1][mid]);
        }
    }

    // Build segtree over euler order positions 0..N-1
    SegTree seg(N);
    vector<int> active(N+1,0);
    for(int i=1;i<=N;i++) active[i] = (color[i]==1);
    seg.build_from_active(active);

    auto query_subtree = [&](int u)->long long{
        int l = tin[u];
        int r = tout[u] + 1;
        NodeAgg agg = seg.query_range(l, r);
        return steiner_vertices_from_agg(agg);
    };

    auto query_complement_subtree = [&](int u)->long long{
        int l = tin[u];
        int r = tout[u] + 1;
        NodeAgg left = seg.query_range(0, l);
        NodeAgg right = seg.query_range(r, N);
        NodeAgg merged = SegTree::mergeAgg(left, right);
        return steiner_vertices_from_agg(merged);
    };

    int Q; cin >> Q;
    while(Q--){
        int t; cin >> t;
        if(t==1){
            int v; cin >> v;
            color[v] ^= 1;
            int pos = tin[v];
            if(color[v]==1){
                seg.update_pos(pos, v);
            }else{
                seg.update_pos(pos, -1);
            }
        }else{
            int x,y; cin >> x >> y;
            if(x==y){
                NodeAgg agg = seg.query_range(0, N);
                cout << steiner_vertices_from_agg(agg) << "\n";
                continue;
            }
            if(is_ancestor(y, x)){
                // neighbor z is the child of y on path to x
                int z = jump_up(x, depthv[x] - depthv[y] - 1);
                cout << query_complement_subtree(z) << "\n";
            }else{
                // component containing x is outside subtree(y), so S = subtree(y)
                cout << query_subtree(y) << "\n";
            }
        }
    }
    return 0;
}
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