Submission #945369

#	Time	Username	Problem	Language	Result	Execution time	Memory
945369		vladilius	Cat Exercise (JOI23_ho_t4)	C++17	0 / 100	0 ms	452 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int msz = 2e5 + 5;
const int lg = 25;
using pii = pair<int, int>;

vector<int> a;

struct dsu{
    vector<int> sz, p, m;
    int n;
    dsu(int ns){
        n = ns;
        p.resize(n + 1);
        sz.resize(n + 1);
        m.resize(n + 1);
        for (int i = 1; i <= n; i++){
            p[i] = m[i] = i;
            sz[i] = 1;
        }
    }
    int get(int v){
        if (v != p[v]){
            p[v] = get(p[v]);
        }
        return p[v];
    }
    void unite(int x, int y){
        x = get(x); y = get(y);
        if (x == y) return;
        if (sz[x] > sz[y]){
            swap(x, y);
        }
        p[x] = y;
        if (a[m[x]] > a[m[y]]){
            m[y] = m[x];
        }
        sz[y] += sz[x];
    }
};

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int n; cin>>n;
    a.resize(n + 1);
    vector<int> b;
    int s = 0;
    for (int i = 1; i <= n; i++){
        cin>>a[i];
        b.push_back(i);
        if (a[i] == n){
            s = i;
        }
    }
    vector<int> g[n + 1];
    for (int i = 1; i < n; i++){
        int a, b; cin>>a>>b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    auto cmp = [&](int x, int y){
        return a[x] < a[y];
    };
    sort(b.begin(), b.end(), cmp);
    vector<bool> used(n + 1);
    dsu T(n + 1);
    vector<int> p(n + 1);
    b.pop_back();
    for (int i: b){
        used[i] = true;
        vector<int> t;
        for (int j: g[i]){
            if (used[j]){
                t.push_back(T.m[T.get(j)]);
            }
        }
        for (int j: g[i]){
            if (used[j]){
                T.unite(i, j);
            }
        }
        sort(t.begin(), t.end(), cmp);
        for (int j = 0; j + 1 < t.size(); j++){
            p[t[j + 1]] = t[j];
        }
        if (!t.empty()) p[i] = t.back();
    }
    fill(used.begin(), used.end(), false);
    vector<int> d(n + 1), pw[n + 1], tin(n + 1), tout(n + 1);
    for (int i = 1; i <= n; i++){
        pw[i].resize(lg);
    }
    int timer = 0;
    function<void(int, int)> fill = [&](int v, int pr){
        tin[v] = timer++;
        pw[v][0] = pr;
        for (int i = 1; i < lg; i++){
            pw[v][i] = pw[pw[v][i - 1]][i - 1];
        }
        for (int i: g[v]){
            if (i == pr) continue;
            d[i] = d[v] + 1;
            fill(i, v);
        }
        tout[v] = timer++;
    };
    fill(1, 1);
    auto check = [&](int x, int y){
        return (tin[x] <= tin[y] && tout[x] >= tout[y]);
    };
    auto lca = [&](int x, int y){
        if (check(x, y)) return x;
        if (check(y, x)) return y;
        for (int i = lg - 1; i >= 0; i--){
            if (!check(pw[x][i], y)){
                x = pw[x][i];
            }
        }
        return pw[x][0];
    };
    auto dist = [&](int x, int y){
        return d[x] + d[y] - 2 * d[lca(x, y)];
    };
    for (int i = 1; i <= n; i++) used[i] = true;
    for (int i = 1; i <= n; i++){
        if (!p[i]){
            used[i] = false;
            continue;
        }
        used[p[i]] = false;
    }
    ll out = 0;
    for (int i = 1; i <= n; i++){
        if (used[i]){
            int v = i;
            ll sum = 0;
            while (p[v] > 0){
                sum += dist(v, p[v]);
                v = p[v];
            }
            out = max(out, sum + dist(s, i));
        }
    }
    cout<<out<<"\n";
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:87:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |         for (int j = 0; j + 1 < t.size(); j++){
      |                         ~~~~~~^~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 7
• Subtask 3: 0 / 7
• Subtask 4: 0 / 10
• Subtask 5: 0 / 20
• Subtask 6: 0 / 23
• Subtask 7: 0 / 26