Submission #458831

#	Time	Username	Problem	Language	Result	Execution time	Memory
458831		JovanB	Min-max tree (BOI18_minmaxtree)	C++17	100 / 100	605 ms	100548 KiB

minmaxtree

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

using ll = long long;
using ld = long double;

const int N = 200000;
const int LOG = 16;

int in[N+5], out[N+5], sz[N+5];
vector <int> graf[N+5];
int par[N+5][LOG+1];

int tjm;

void dfs_lca(int v, int p){
    in[v] = ++tjm;
    sz[v] = 1;
    par[v][0] = p;
    for(int j=1; j<=LOG; j++) par[v][j] = par[par[v][j-1]][j-1];
    for(auto c : graf[v]){
        if(c == p) continue;
        dfs_lca(c, v);
        sz[v] += sz[c];
    }
    out[v] = ++tjm;
}

bool is_parent(int a, int b){
    return a == 0 || (in[a] <= in[b] && out[b] <= out[a]);
}

int lca(int a, int b){
    if(is_parent(a, b)) return a;
    for(int j=LOG; j>=0; j--) if(!is_parent(par[a][j], b)) a = par[a][j];
    return par[a][0];
}

int qa[N+5], qb[N+5], qc[N+5];
char typ[N+5];

vector <int> vec[2][N+5];
set <int> vals[2][N+5];

int gde[N+5];
int mxl[N+5], mnr[N+5];

const int INF = 1000000007;

void dodaj(int v){
    sort(vec[0][v].begin(), vec[0][v].end());
    reverse(vec[0][v].begin(), vec[0][v].end());
    for(auto x : vec[0][v]){
        if(x > 0) vals[0][gde[v]].insert(x);
        else vals[0][gde[v]].erase(-x);
    }
    sort(vec[1][v].begin(), vec[1][v].end());
    reverse(vec[1][v].begin(), vec[1][v].end());
    for(auto x : vec[1][v]){
        if(x > 0) vals[1][gde[v]].insert(x);
        else vals[1][gde[v]].erase(-x);
    }
}

void dfs_calc(int v, int p){
    mnr[v] = INF;
    int mx = 0;
    for(auto c : graf[v]){
        if(c == p) continue;
        dfs_calc(c, v);
        if(sz[c] >= sz[mx]) mx = c;
    }
    if(!mx){
        gde[v] = v;
        dodaj(v);
        if(vals[0][gde[v]].size()) mxl[v] = *vals[0][gde[v]].rbegin();
        if(vals[1][gde[v]].size()) mnr[v] = *vals[1][gde[v]].begin();
        return;
    }
    gde[v] = gde[mx];
    for(auto c : graf[v]){
        if(c == p || c == mx) continue;
        for(auto x : vals[0][gde[c]]) vals[0][gde[v]].insert(x);
        for(auto x : vals[1][gde[c]]) vals[1][gde[v]].insert(x);
        vals[0][gde[c]].clear();
        vals[1][gde[c]].clear();
    }
    dodaj(v);
    if(vals[0][gde[v]].size()) mxl[v] = *vals[0][gde[v]].rbegin();
    if(vals[1][gde[v]].size()) mnr[v] = *vals[1][gde[v]].begin();
}

map <int, int> kome;
set <int> bgraf[2*N+5];
int val[N+5];

set <pair <int, int>> q;

void clr(int v){
    for(auto c : bgraf[v]){
        q.erase({bgraf[c].size(), c});
        assert(bgraf[c].find(v) != bgraf[c].end());
        bgraf[c].erase(v);
        if(bgraf[c].size()) q.insert({bgraf[c].size(), c});
    }
}

int main(){
    ios_base::sync_with_stdio(false), cin.tie(0);
    cout.precision(10);
    cout << fixed;

    int n;
    cin >> n;
    for(int i=1; i<n; i++){
        int a, b;
        cin >> a >> b;
        graf[a].push_back(b);
        graf[b].push_back(a);
    }
    dfs_lca(1, 0);
    int qrs;
    cin >> qrs;
    for(int t=1; t<=qrs; t++){
        cin >> typ[t] >> qa[t] >> qb[t] >> qc[t];
        qc[t]++;
        kome[qc[t]] = t;
        if(typ[t] == 'm'){
            vec[0][qa[t]].push_back(qc[t]);
            vec[0][qb[t]].push_back(qc[t]);
            vec[0][lca(qa[t], qb[t])].push_back(-qc[t]);
        }
        else{
            vec[1][qa[t]].push_back(qc[t]);
            vec[1][qb[t]].push_back(qc[t]);
            vec[1][lca(qa[t], qb[t])].push_back(-qc[t]);
        }
    }
    dfs_calc(1, 0);
    for(int i=2; i<=n; i++){
        if(mxl[i]){
            int v = kome[mxl[i]];
            bgraf[v].insert(N + i);
            bgraf[N + i].insert(v);
        }
        if(mnr[i] != INF){
            int v = kome[mnr[i]];
            bgraf[v].insert(N + i);
            bgraf[N + i].insert(v);
        }
    }
    for(int i=1; i<=qrs; i++) q.insert({bgraf[i].size(), i});
    for(int i=2; i<=n; i++) q.insert({bgraf[N + i].size(), N + i});
    while(!q.empty()){
        int v = q.begin()->second;
        q.erase(q.begin());
        if(bgraf[v].empty()) continue;
        if(bgraf[v].size() > 2){
            for(auto c : bgraf[v]){
                //assert(bgraf[c].size() >= bgraf[v].size());
                assert(q.find({bgraf[c].size(), c}) != q.end());
            }
        }
        int c = *bgraf[v].begin();
        if(v > N) swap(v, c);
        val[c - N] = qc[v];
        q.erase({bgraf[v].size(), v});
        q.erase({bgraf[c].size(), c});
        bgraf[v].erase(c);
        bgraf[c].erase(v);
        clr(v);
        clr(c);
        bgraf[v].clear();
        bgraf[c].clear();
    }
    for(int i=2; i<=n; i++){
        cout << par[i][0] << " " << i << " ";
        if(val[i]) cout << val[i] - 1 << "\n";
        else if(mxl[i]) cout << mxl[i] - 1 << "\n";
        else if(mnr[i] != INF) cout << mnr[i] - 1 << "\n";
        else cout << "1\n";
    }
    return 0;
}

/*
6
1 2
2 4
1 6
1 3
6 5
2
m 4 1 2
M 4 6 3
*/

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