제출 #1286973

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1286973		al95ireyiz	Split the Attractions (IOI19_split)	C++20	0 / 100	712 ms	1114112 KiB

split

#pragma GCC optimize("O3", "fast-math", "unroll-loops", "no-stack-protector")
#include <bits/stdc++.h>
using namespace std;
#if !defined(ONLINE_JUDGE) and !defined(EVAL)
#include "template/debug.h"
#else
#define d(x...)
#endif
#define fr first
#define er erase
#define in insert
#define sc second
#define ll long long
#define pb push_back
#define vll vector<ll>
#define pll pair<ll,ll>
#define len(x) (ll) x.size()
#define all(x) x.begin(),x.end()
const ll INF = 1e9, INFL = 1e18;
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll maxn = 1e5 + 5;

ll n, m, k = 0;

#include "split.h"
mt19937 rng(clock());

vll g[maxn];
ll sz[maxn];

void dfs(ll u, ll p = -1){
    sz[u] ++;
    for(auto v : g[u]){
        if(v == p) continue;
        dfs(v, u);
        sz[u] += sz[v];
    }
}
vll ve;
void dfs2(ll u, ll rest, ll p = -1){
    ve.pb(u);
    if(len(ve) >= k) return;
    for(auto v : g[u]){
        if(v == rest or v == p) continue;
        dfs2(v, rest, u);
        if(len(ve) >= k) return;
    }
}
pair<vll, vll>f(ll a, ll b){
    if(a > b) swap(a, b);
    // 7 balliq subtask : cycle (AC)

    // 11 balliq subtask : a = 1 (AC)

    // 22 balliq subtask : tree
    // birde burdan sonra artiq alinmayan hallar var
    // eger treedise, demeli ele node tapa bilerik ki, ordan rootlayanda, ele bir v subtreesi olsun ki, len(v) >= a olsun,
    // ve n - len(v) >= b olsun.
    // onda bize bele v-lerden elesi lazimdi ki, minimum olsun. v-nin subtreelerinin hec biri ucun size >= a olmasin.

    // aglima yol gelmir birinci random ile kecirmeyi yoxluyacam
    set<ll>s;
    auto get = [&]() -> ll{
        if(len(s) == n) return -1;
        ll x = rng() % n;
        while(s.find(x) != s.end()) x = rng() % n;
        s.in(x);
        return x;
    };
    vll ax, bx;
    for(ll tt = 0; tt <= 500; tt ++){
        ll r = get();
        if(r == -1) break;
        for(ll i = 0; i < n; i ++) sz[i] = 0;
        dfs(r);
        ll f = 0;
        for(auto ch : g[r]){
            if(sz[ch] >= a and n - sz[ch] >= b){
                f = ch;
                break;
            }
        }
        if(f){
            k = a;
            ve.clear();
            dfs2(f, r);
            ax = ve;

            k = b;
            ve.clear();
            dfs2(r, f);
            bx = ve;
            break;
        }
    }
    return {ax, bx};
}
vector<int> find_split(int _n, int _a, int _b, int _c, vector<int> p, vector<int> q) {
    n = _n;
    for(ll i = 0; i < len(p); i ++){
        g[p[i]].pb(q[i]), g[q[i]].pb(p[i]);
    }
    vector<int>cv(n);
    if(_a <= _c and _b <= _c){
        auto [ax, bx] = f(_a, _b);
        if(_a > _b) swap(ax, bx);
        if(len(ax) != _a) return cv;
        cv.assign(n, 3);
        for(auto i : ax) cv[i] = 1;
        for(auto i : bx) cv[i] = 2;
    }
    else if(_a <= _b and _c <= _b){
        auto [ax, cx] = f(_a, _c);
        if(_a > _c) swap(ax, cx);
        if(len(ax) != _a) return cv;
        cv.assign(n, 2);
        for(auto i : ax) cv[i] = 1;
        for(auto i : cx) cv[i] = 3;
    }
    else{
        auto [bx, cx] = f(_b, _c);
        if(_b > _c) swap(bx, cx);
        if(len(bx) != _b) return cv;
        cv.assign(n, 1);
        for(auto i : bx) cv[i] = 2;
        for(auto i : cx) cv[i] = 3;
    }
    return cv;
}
// void _() {

// }
// signed main() {
//     ll tm = clock();
//     cin.tie(0)->sync_with_stdio(0);
//     ll t = 1;
//     // cin >> t;
//     for(ll tt = 1; tt <= t; tt ++) _();
//     cerr << "\n\033[1;31mTime: \033[1;30m" \
//         << (double)(clock()-tm)/1000000 << "\033[1;32m seconds\n";
// }

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