Submission #351393

#	Time	Username	Problem	Language	Result	Execution time	Memory
351393		amunduzbaev	Split the Attractions (IOI19_split)	C++14	100 / 100	229 ms	20332 KiB

split

#include <bits/stdc++.h>
#include "split.h"

#ifndef EVAL
#include "grader.cpp"
#endif

using namespace std;
 
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define ll long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define fastios ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define vll vector<ll>
#define vii vector<int>
#define vpii vector<pii>
#define vpll vector<pll>
#define cnt(a)__builtin_popcount(a)
template<class T> bool umin(T& a, const T& b) {return a > b? a = b, true:false;}
template<class T> bool umax(T& a, const T& b) {return a < b? a = b, true:false;}

using namespace std;

const int N = 2e5+5;

vpii dd, ex;
vii edges[N];
int par[N], sz[N], sis[N];
int nn, rr;

void dfs(int u, int p){
	sis[u] = 1;
	for(auto x:edges[u]){
		if(x == p) continue;
		dfs(x, u);
		sis[u] += sis[x];
	}
}

int dfs_centr(int u, int p){
	int mx = 0, in = 0;
	for(auto x:edges[u]){
		if(x == p) continue;
		if(sis[x] > mx) mx = sis[x], in = x;
	}
	//assert(in != -1);
	if(mx*2 <= nn) return u; 
	return dfs_centr(in, u);
	//return u;
}

/* ###############################################################################
 * dsu part
 * ############################################################################### */

int f(int x){
	if(x == par[x]) return x;
	return par[x] = f(par[x]);
}

bool  merge(int a, int b){
	a = f(a), b = f(b);
	if(a == b) return 0;
	par[b] = a;
	sz[a] += sz[b];
	return 1;
}

void add_dsu(int u, int p){
	for(auto x:edges[u]){
		if(x == p) continue;
		merge(u, x);
		add_dsu(x, u);
	}
}

/* ###############################################################################
 * solving part
 * ############################################################################### */

set<pii> ss;

bool check(){
	if(!sz(ss)) return 0;
	auto x = --ss.end();
	return (*x).ff >= dd[0].ff;
}

vector<int> res;
int siz;
void s_a(int u){
	if(siz == dd[0].ff) return;
	res[u] = dd[0].ss, siz++;
	for(auto x:edges[u]){
		if(siz == dd[0].ff) return;
		if(f(x) == f(u) && res[x] == 0) s_a(x);
	}
}

void s_b(int u){
	if(siz == dd[1].ff) return;
	res[u] = dd[1].ss, siz++;
	for(auto x:edges[u]){
		if(siz == dd[1].ff) return;
		if(res[x] == 0) s_b(x);
	}
}

vii solve(){
	siz = 0; 
	res.assign(nn, 0);
	s_a((*--ss.end()).ss);
	siz = 0;
	s_b(rr);
	for(int i=0;i<nn;i++) if(res[i] == 0) res[i] = dd[2].ss; 
	
	return res;
}

/* ###############################################################################
 * end of solving part
 * ############################################################################### */

vii find_split(int n, int a, int b, int c, vector<int> p, vector<int> q) {
	nn = n;
	dd.pb(mp(a, 1));
	dd.pb(mp(b, 2));
	dd.pb(mp(c, 3));
	
	sort(all(dd));
	for(int i=0;i<n;i++) par[i] = i, sz[i] = 1;
	
	for(int i=0;i<sz(p);i++){
		int a = p[i], b = q[i];
		if(merge(a, b)){
			edges[a].pb(b);
			edges[b].pb(a);
		}else ex.pb({a, b});
	}
	dfs(0, -1);
	rr = dfs_centr(0, -1);
	
	for(int i=0;i<n;i++) par[i] = i, sz[i] = 1;
	for(auto x:edges[rr]){
		add_dsu(x, rr);
		ss.insert(mp(sz[f(x)], f(x)));
	}
	if(check()) return solve();
	
	for(auto x : ex){
		int a = x.ff, b = x.ss;
		int pa = f(a), pb = f(b);
		if(pa == pb || b == rr || a == rr) continue;
		ss.erase({sz[pa], pa});
		ss.erase({sz[pb], pb});
		merge(pa, pb);
		ss.insert({sz[f(pa)], f(pa)});
		edges[a].pb(b);
		edges[b].pb(a);
		if(check()) return solve();
	}
	res.assign(n, 0);
	return res;
}

/*

6 5
2 2 2
0 1
0 2
0 3
0 4
0 5

9 11 2 3 4
0 1
0 2
0 4
0 3
0 5
0 6
0 8
1 7
3 7
4 5
5 6

*/

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 22 / 22
• Subtask 4: 24 / 24
• Subtask 5: 36 / 36