Submission #1133707

#	Time	Username	Problem	Language	Result	Execution time	Memory
1133707		Gray	Min-max tree (BOI18_minmaxtree)	C++20	36 / 100	1095 ms	28516 KiB

minmaxtree

#include <bits/stdc++.h>
#include <cassert>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define ff first
#define ss second
#define ln "\n"
#define mp make_pair

#define INF 2e18
#define MOD 1e9+7

vector<pair<ll, ll>> up;
vector<vector<ll>> add, A;
vector<pair<ll, ll>> e, bound;
vector<ll> sz;
void sortsz(ll u, ll p){
    sz[u]=add[u].size(); ll mx=0;
    for (auto &i:A[u]){
        ll v = e[i].ff^e[i].ss^u;
        if (v==p) continue;
        if (sz[v]>mx) swap(A[u][0], i);
        mx=max(mx, sz[v]);
        sz[u]+=sz[v];
    }
}

void dfs(ll u, ll p, set<pair<ll, ll>> &upMN, set<pair<ll, ll>> &upMX){
    set<pair<ll, ll>> tupMN, tupMX; bool first=1;
    for (auto i:A[u]){
        ll v = e[i].ff^e[i].ss^u;
        if (v==p) continue;
        if (first){
            dfs(v, u, upMN, upMX);
            if (!upMN.empty()) bound[i].ff = (*upMN.rbegin()).ss;
            if (!upMX.empty()) bound[i].ss = (*upMX.begin()).ss;
            first=0;
        }else{
            tupMN.clear(); tupMX.clear();
            dfs(v, u, tupMN, tupMX);
            if (!tupMN.empty()) bound[i].ff = (*tupMN.rbegin()).ss;
            if (!tupMX.empty()) bound[i].ss = (*tupMX.begin()).ss;
            for (auto ch:tupMN){
                if(upMN.count(ch)) upMN.erase(ch);
                else upMN.insert(ch);
            }
            for (auto ch:tupMX){
                if (upMX.count(ch)) upMX.erase(ch);
                else upMX.insert(ch);
            }
        }
    }

    for (auto i:add[u]){
        if (up[i].ff){
            if (upMN.count({up[i].ss, i})) upMN.erase({up[i].ss, i});
            else upMN.insert({up[i].ss, i});
        }else {
            if (upMX.count({up[i].ss, i})) upMX.erase({up[i].ss, i});
            else upMX.insert({up[i].ss, i});
        }
    }
}

struct Kuhn{
    vector<vector<ll>> A;
    vector<ll> match, vis;
    ll na, nb, cnt;
    Kuhn(ll _na, ll _nb){
        na=_na; nb=_nb; cnt=0;
        match.resize(nb, -1); vis.resize(na, 0);
        A.resize(na);
    }
    void add_edge(ll u, ll v){
        A[u].push_back(v);
    }
    bool try_kuhn(ll u){
        if (vis[u]==cnt) return 0;
        vis[u]=cnt;
        for (auto v:A[u]){
            if (match[v]==-1){
                match[v]=u;
                return 1;
            }
        }
        for (auto v:A[u]){
            if (try_kuhn(match[v])){
                match[v]=u;
                return 1;
            }
        }
        return 0;
    }
    void run(){
        for (ll i=0; i<na; i++){
            cnt++;
            try_kuhn(i);
        }
    }
};

void solve(){
    ll n; cin >> n;
    A.resize(n+1); e.resize(n-1); bound.resize(n-1, {-1, -1});
    for (ll i=0; i<n-1; i++){
        ll u, v; cin >> u >> v; e[i] = {u, v};
        A[u].push_back(i); A[v].push_back(i);
    }
    ll k; cin >> k; up.resize(k);
    add.resize(n+1);
    for (ll i=0; i<k; i++){
        char typ; ll u, v, w; cin >> typ >> u >> v >> w;
        up[i] = {typ=='m', w};
        add[u].push_back(i);
        add[v].push_back(i);
    }
    set<pair<ll, ll>> upMN, upMX;
    sz.resize(n+1); sortsz(1, 1);
    dfs(1, 1, upMN, upMX);
    for (ll i=0; i<n-1; i++){
        // cout << bound[i].ff << " " << bound[i].ss << endl;
        assert((bound[i].ff==-1 or bound[i].ss==-1 or up[bound[i].ff].ss<=up[bound[i].ss].ss));
    }
    Kuhn match(k, n-1);
    for (ll i=0; i<n-1; i++){
        if (bound[i].ff!=-1) match.add_edge(bound[i].ff, i);
        if (bound[i].ss!=-1) match.add_edge(bound[i].ss, i);
    }
    match.run();
    for (ll i=0; i<n-1; i++){
        cout << e[i].ff << " " << e[i].ss << " ";
        if (match.match[i]==-1) cout << (bound[i].ff!=-1?up[bound[i].ff].ss:0) << ln;
        else cout << up[match.match[i]].ss << ln;
    }
}
int main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    auto start = chrono::high_resolution_clock::now();
    ll t=1;
    // cin >> t;
    while (t--) solve();
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    cout << setprecision(0) << fixed << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
}

• Subtask 1: 7 / 7
• Subtask 2: 0 / 22
• Subtask 3: 29 / 29
• Subtask 4: 0 / 42