oj.uz

답안 #1092538

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1092538 2024-09-24T10:42:58 Z onbert Mergers (JOI19_mergers) C++17
0 / 100
 117 ms 74576 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 5e5 + 5, maxk = 5e5+5, lg = 20;
int n, k;
vector<int> ADJ[maxn];
int A[maxn];

int SZ[maxn], FA[maxn], newid[maxn], lim[maxn], cnt = 0;
bool cmp(int x, int y) {
    return SZ[x] > SZ[y];
}
void DFS0(int u) {
    SZ[u] = 1;
    for (int v:ADJ[u]) {
        FA[v] = u;
        ADJ[v].erase(find(ADJ[v].begin(), ADJ[v].end(), u));
        DFS0(v);
        SZ[u] += SZ[v];
    }
    sort(ADJ[u].begin(), ADJ[u].end(), cmp);
}
void DFS1(int u) {
    cnt++;
    newid[u] = cnt;
    for (int v:ADJ[u]) DFS1(v);
    lim[newid[u]] = cnt;
}

vector<int> adj[maxn];
int fa[maxn], sz[maxn];
vector<int> mem[maxk];
int a[maxn];

int st[maxn][lg];
void dfs0(int u) {
    for (int i=1;i<lg;i++) {
        if (!st[u][i-1] || !st[st[u][i-1]][i-1]) break;
        st[u][i] = st[st[u][i-1]][i-1];
    }
    for (int v:adj[u]) {
        st[v][0] = u;
        dfs0(v);
    }
}

int psum[maxn];
int lca(int u, int c) {
    int l = mem[c][0], r = mem[c].back();
    for (int i=lg-1;i>=0;i--) if (st[u][i]) {
        int v = st[u][i];
        if (!(v<=l && r<=lim[v])) u = v;
    }
    // cout << c << " " << l << " " << r << endl;
    if (!(u<=l && r<=lim[u])) u = fa[u];
    return u;
}

bool sep[maxn];
bool sepleaf[maxn];

int sum[maxn];
int dead = 0, ans = 0;
bool frst = false;

void dfs1(int u, int minus) {
    // cout << u << " " << minus << endl;
    if (minus==0 && sep[u]) frst = true;
    if (sum[lim[u]] - sum[u-1] - minus == 1 && sep[u]) dead++;
    if (adj[u].size()==0) return;
    vector<pair<int,int>> vec;
    for (int v:adj[u]) {
        vec.push_back({sum[lim[v]] - sum[v-1], v});
    }
    sort(vec.begin(), vec.end());
    int l = 0, r = 1e18;
    while (l<r) {
        int mid = (l+r)/2, used = 0;
        for (auto [x, y]:vec) used += max(x - mid, (int)0);
        if (used <= minus) r = mid;
        else l = mid+1;
    }
    for (auto &[x, y]:vec) x = min(x, l);
    int total = sum[lim[u]] - sum[u] - minus;
    if (vec[0].first <= (total+1)/2) {
        ans += (total+1)/2;
        return;
    }
    int rest = total - vec[0].first;
    vec[0].first -= rest;
    int v = vec[0].second;
    ans += rest;
    dfs1(v, sum[lim[v]] - sum[v-1] - vec[0].first);
}


signed main() {
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> n >> k;
    for (int i=1;i<=n-1;i++) {
        int u, v;
        cin >> u >> v;
        ADJ[u].push_back(v), ADJ[v].push_back(u);
    }
    for (int i=1;i<=n;i++) cin >> A[i];
    DFS0(1);
    DFS1(1);
    // for (int i=1;i<=n;i++) cout << newid[i] << " "; cout << endl;
    // for (int i=1;i<=n;i++) cout << lim[i] << " "; cout << endl;
    for (int i=1;i<=n;i++) {
        for (int j:ADJ[i]) adj[newid[i]].push_back(newid[j]);
        if (i!=1) fa[newid[i]] = newid[FA[i]];
        else fa[i] = 0;
        sz[newid[i]] = SZ[i];
    }
    for (int i=1;i<=n;i++) {
        a[newid[i]] = A[i];
        mem[A[i]].push_back(newid[i]);
    }
    dfs0(1);
    for (int i=1;i<=k;i++) {
        sort(mem[i].begin(), mem[i].end());
        psum[lca(mem[i][0], i)] += mem[i].size();
    }
    for (int i=1;i<=n;i++) psum[i] += psum[i-1];

    for (int i=2;i<=n;i++) {
        sep[i] = (psum[lim[i]] - psum[i-1] == lim[i] - i + 1);
        // cout << psum[lim[i]] - psum[i-1] << " " << lim[i] - i + 1 << endl;
    }
    // for (int i=1;i<=n;i++) cout << sep[i]; cout << endl;
    
    for (int i=1;i<=n;i++) sum[i] = sum[i-1] + sep[i];

    for (int i=1;i<=n;i++) sepleaf[i] = (sep[i] && sum[lim[i]] - sum[i-1] == 1);

    bool add = false;
    for (int i=2;i<=n;i++) if (sum[lim[i]] - sum[i-1] == sum[n] && sep[i] && !sepleaf[i]) add = true;

    int ans = 0;
    for (int i=1;i<=n;i++) ans += sepleaf[i];
    cout << (ans+1)/2 + add << endl;
    // if (sum[n]==0) {
    //     cout << 0 << endl;
    //     return 0;
    // }
    // dfs1(1, 0);
    // // assert(dead<=1);
    // cout << ans + (dead+1)/2 << endl;
}

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 35672 KB Output is correct
2 Correct 16 ms 35676 KB Output is correct
3 Incorrect 16 ms 35676 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 35672 KB Output is correct
2 Correct 16 ms 35676 KB Output is correct
3 Incorrect 16 ms 35676 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 35672 KB Output is correct
2 Correct 16 ms 35676 KB Output is correct
3 Incorrect 16 ms 35676 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 57 ms 66632 KB Output is correct
2 Correct 75 ms 68936 KB Output is correct
3 Correct 18 ms 36700 KB Output is correct
4 Correct 17 ms 36700 KB Output is correct
5 Correct 16 ms 35676 KB Output is correct
6 Correct 18 ms 35672 KB Output is correct
7 Correct 18 ms 36656 KB Output is correct
8 Correct 97 ms 68432 KB Output is correct
9 Correct 18 ms 36700 KB Output is correct
10 Correct 68 ms 67616 KB Output is correct
11 Correct 16 ms 35672 KB Output is correct
12 Correct 89 ms 68180 KB Output is correct
13 Correct 93 ms 68432 KB Output is correct
14 Correct 98 ms 69712 KB Output is correct
15 Correct 61 ms 66372 KB Output is correct
16 Correct 19 ms 36700 KB Output is correct
17 Correct 19 ms 35676 KB Output is correct
18 Correct 69 ms 68468 KB Output is correct
19 Correct 117 ms 74576 KB Output is correct
20 Correct 18 ms 36700 KB Output is correct
21 Incorrect 17 ms 35672 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 19 ms 35672 KB Output is correct
2 Correct 16 ms 35676 KB Output is correct
3 Incorrect 16 ms 35676 KB Output isn't correct
4 Halted 0 ms 0 KB -