Submission #722876

#	Time	Username	Problem	Language	Result	Execution time	Memory
722876		victor_gao	Split the Attractions (IOI19_split)	C++17	40 / 100	148 ms	22692 KiB

split

#include "split.h"
#include <bits/stdc++.h>
#define pii pair<int,int>
#define x first
#define y second
#define N 100015
using namespace std;
vector<int>g[N],tre[N],leaf1,leaf2,res;
int sz[N],A,B,C,deg[N],mx[N],n;
bool vis[N];
void get_tree(int p){
	vis[p]=1;
	for (auto i:g[p]){
		if (!vis[i]){
			tre[i].push_back(p);
			tre[p].push_back(i);
			get_tree(i);
		}
	}
}
void count_size(int p,int lp){
	sz[p]=1; deg[p]=tre[p].size();
	for (auto i:tre[p]){
		if (i!=lp){
			count_size(i,p);
			mx[p]=max(mx[p],sz[i]);
			sz[p]+=sz[i];
		}
	}
	mx[p]=max(mx[p],(n-sz[p]));
}
void dfs1(int p,int lp){
	res[p]=1;
	if (tre[p].size()==1)
		leaf1.push_back(p);
	for (auto i:tre[p])
		if (i!=lp)
			dfs1(i,p);
}
void dfs2(int p,int lp){
	res[p]=2;
	if (tre[p].size()==1)
		leaf2.push_back(p);
	for (auto i:tre[p])
		if (i!=lp)
			dfs2(i,p);
}
void solve(){
	res.resize(n+1,0);
	get_tree(1);
//	cout<<"OK\n";
	count_size(1,0);
//	cout<<"Count finish\n";
//	for (int i=1;i<=n;i++)
//		cout<<sz[i]<<' ';
//	cout<<'\n';
	int mid=0;
//	cout<<"need "<<A<<" "<<B<<" "<<C<<'\n';
	for (int i=1;i<=n;i++){
		if (mx[i]>=A&&n-mx[i]>=B){
		//	cout<<"get "<<i<<' '<<mx[i]<<"\n";
			mid=i;
			break;
		}
		else if (mx[i]>=B&&n-mx[i]>=A){
		//	cout<<"get "<<i<<" "<<mx[i]<<'\n';
			mid=i;
			break;
		}
	}
	//cout<<"root "<<mid<<"\n";
	if (mid==0) return;
	count_size(mid,0);
	vector<pii>all;
	for (auto i:tre[mid])
		all.push_back({sz[i],i});
	sort(all.begin(),all.end());
	int now1=0,now2=0;
	if (all.back().x>=B){
		dfs2(all.back().y,mid);
		now2=all.back().x;
		for (int i=0;i<all.size()-1;i++){
			dfs1(all[i].y,mid);
			now1+=all[i].x;
		}
		res[mid]=1; now1++;
	}
	else {
		dfs1(all.back().y,mid);
		now1=all.back().x;
		for (int i=0;i<all.size()-1;i++){
			dfs2(all[i].y,mid);
			now2+=all[i].x;
		}
		res[mid]=2; now2++;
	}
	while (now1>A){
		int out=leaf1.back(); leaf1.pop_back();
		res[out]=3; now1--;
		for (auto i:tre[out]){
			deg[i]--;
			if (deg[i]==1)
				leaf1.push_back(i);
		}
	}
	while (now2>B){
		int out=leaf2.back(); leaf2.pop_back();
		res[out]=3; now2--;
		for (auto i:tre[out]){
			deg[i]--;
			if (deg[i]==1)
				leaf2.push_back(i);
		}
	}
}
vector<int> find_split(int _n, int a, int b, int c, vector<int> p, vector<int> q) {
	n=_n;
	vector<pii>s={{a,1},{b,2},{c,3}};
	sort(s.begin(),s.end());
	A=s[0].x; B=s[1].x; C=s[2].x;
	for (int i=0;i<p.size();i++){
		g[p[i]+1].push_back(q[i]+1);
		g[q[i]+1].push_back(p[i]+1);
	}
	solve();
	vector<int>ans; ans.resize(n,0);
	if (res[1]==0) return ans;
	for (int i=1;i<=n;i++)
		ans[i-1]=(s[res[i]-1].y);
	int sz[4]={};
	for (auto i:ans)
		sz[i]++;
	assert(sz[1]==a&&sz[2]==b&&sz[3]==c);
	return ans;
}

Compilation message (stderr)

split.cpp: In function 'void solve()':
split.cpp:82:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   82 |   for (int i=0;i<all.size()-1;i++){
      |                ~^~~~~~~~~~~~~
split.cpp:91:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |   for (int i=0;i<all.size()-1;i++){
      |                ~^~~~~~~~~~~~~
split.cpp: In function 'std::vector<int> find_split(int, int, int, int, std::vector<int>, std::vector<int>)':
split.cpp:121:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |  for (int i=0;i<p.size();i++){
      |               ~^~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 22 / 22
• Subtask 4: 0 / 24
• Subtask 5: 0 / 36