Submission #858230

#	Time	Username	Problem	Language	Result	Execution time	Memory
858230		Danilo21	Closing Time (IOI23_closing)	C++17	8 / 100	89 ms	53296 KiB

closing

#include <bits/stdc++.h>

#define ll long long
#define ld long double
#define pb push_back
#define fi first
#define se second
#define en '\n'
#define sp ' '
#define tb '\t'
#define ri(n) int n; cin >> n
#define rl(n) ll n; cin >> n
#define rs(s) string s; cin >> s
#define rc(c) char c; cin >> c
#define rv(v) for (auto &x : v) cin >> x
#define pven(v) for (auto x : v) cout << x << en
#define pv(v) for (auto x : v) cout << x << sp; cout << en
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define yes cout << "YES" << en
#define no cout << "NO" << en
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
#define ssort(a, b) if (a < b) swap(a, b)
#define bitcnt(a) (__builtin_popcountll(a))
#define bithigh(a) (63-__builtin_clzll(a))
#define lg bithigh
#define highpow(a) (1LL << (ll)lg(a))

using namespace std;

const ll LINF = 2e18;
const int mxN = 1e6+10, INF = 2e9;
ll n, x, y, k, a[mxN];
vector<array<ll, 2> > g[mxN];
bool vis[2][mxN];

int BFS(){

    priority_queue<array<ll, 3>,
            vector<array<ll, 3> >,
            greater<array<ll, 3> > > pq;
    pq.push({0, x, 0});
    pq.push({0, y, 1});
    vis[0][x] = vis[1][y] = 1;
    int cnt = 0;
    ll sum = 0;
    while (pq.size()){
        auto [d, s, t] = pq.top(); pq.pop();
        if (sum + d > k) break;
        sum += d;
        a[s] = d;
        cnt++;
        for (auto [u, w] : g[s]){
            if (!vis[t][u]){
                pq.push({max(0LL, d + w - a[u]), u, t});
                vis[t][u] = 1;
            }
        }
    }
    return cnt;
}

int Solve1(){ return BFS(); }

ll idx[mxN], dist[2][mxN], pre[3][mxN];

int Next(int s){

    for (auto [u, w] : g[s])
        if (!~idx[u]) return u;
    return -1;
}

void dfs(int s, int p, ll d, int t){

    dist[t][s] = d;
    for (auto [u, w] : g[s])
        if (u^p) dfs(u, s, d+w, t);
}

int Solve2(){

    int s = 0;
    for (; s < n; s++)
        if (g[s].size() == 1)
            break;
    for (int i = 0; i < n; i++)
        idx[i] = -1;
    int i = 0;
    while (~s){
        idx[s] = i;
        s = Next(s);
        i++;
    }
    if (idx[x] > idx[y]) swap(x, y);
    dfs(x, -1, 0, 0);
    dfs(y, -1, 0, 1);
    for (int i = 0; i < n; i++){
        pre[0][i] = dist[0][i];
        pre[1][i] = dist[1][i];
        pre[2][i] = max(dist[0][i], dist[1][i]);
    }
    for (int i = 1; i < n; i++)
        for (int j = 0; j < 3; j++)
            pre[j][i] += pre[j][i-1];

    return -1;
}

int par[mxN];

void Par(int s, int p){

    par[s] = p;
    for (auto [u, w] : g[s])
        if (u^p) Par(u, s);
}

int Solve3(){

    Par(x, -1);
    vector<int> path;
    int s = y;
    while (~s){
        path.pb(s);
        s = par[s];
    }
    dfs(x, -1, 0, 0);
    dfs(y, -1, 0, 1);
    int ans = BFS();
    return ans;
}

ll Dist(int s, int p, ll d){

    if (s == y) return d;
    ll dist = 0;
    for (auto [u, w] : g[s])
        if (u^p) smax(dist, Dist(u, s, d + w));
    return dist;
}

int Solve(){

    if (Dist(x, -1, 0) > 2*k) return Solve1();
    int mx = 0;
    for (int i = 0; i < n; i++)
        smax(mx, (int)g[i].size());
    if (mx <= 2) return Solve2();
    return Solve3();
}

int max_score(int N, int X, int Y, long long K, vector<int> U, vector<int> V, vector<int> W){

    n = N; k = K;
    x = X; y = Y;
    for (int i = 0; i < n-1; i++){
        g[U[i]].pb({V[i], W[i]});
        g[V[i]].pb({U[i], W[i]});
    }
    int ans = Solve();
    for (int i = 0; i < n; i++){
        g[i].clear();
        vis[0][i] = vis[1][i] = 0;
        a[i] = 0;
    }
    return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 0 / 9
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 9
• Subtask 6: 0 / 11
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17