Submission #677243

#	Time	Username	Problem	Language	Result	Execution time	Memory
677243		amirhoseinfar1385	Tug of War (BOI15_tug)	C++17	18 / 100	3099 ms	3924 KiB

tug

#include<bits/stdc++.h>
using namespace std;
int n,k;
vector<pair<pair<int,int>,int>>all;
vector<set<int>>fa,fb;
int res=0,now=0;
int unnow=0;
vector<int>vis;
vector<int>allp;
vector<int>bf;
set<int>alla,allb;
void del(int u,int z){
	if(u==-1||vis[u]==1){
		return ;
	}
	vis[u]=1;
	int next=-1;
	if(z==1){
		allb.insert(all[u].first.second);
		unnow-=all[u].second;
		fb[all[u].first.second].erase(u);
		fa[all[u].first.first].erase(u);
		if((int)fa[all[u].first.first].size()==1){
			next=*(fa[all[u].first.first].begin());
		}
	}
	else{
		unnow+=all[u].second;
		alla.insert(all[u].first.first);
		fb[all[u].first.second].erase(u);
		fa[all[u].first.first].erase(u);
		if((int)fb[all[u].first.second].size()==1){
			next=*(fb[all[u].first.second].begin());
		}
	}
	del(next,(z^1));
}

void bfs(int z){
	if(bf.size()==0){
		return ;
	}
//	cout<<bf[0]<<" "<<z<<" "<<allp.size()<<endl;
	vis[bf[0]]=1;
	for(auto x:bf){
		if(z==1){
			res-=all[x].second;
			allb.insert(all[x].first.second);
			fb[all[x].first.second].erase(x);
		}
		else{
			res+=all[x].second;
			alla.insert(all[x].first.first);
			fa[all[x].first.first].erase(x);
		}
	}
	vector<int>fake;
	for(auto x:bf){
		if(z==1){
			for(auto y:fb[all[x].first.second]){
				int v=y;
				if(vis[v]==0){
					vis[v]=1;
					fake.push_back(v);
				}
			}
		}
		else{
			for(auto y:fa[all[x].first.first]){
				int v=y;
				if(vis[v]==0){
					vis[v]=1;
					fake.push_back(v);
				}
			}
		}
	}
	bf.swap(fake);
	bfs((z^1));
}
const int mid=20*30000+10;
void solve(){
	bitset<mid*2>bt;
	bt[mid]=1;
	for(int i=0;i<(int)allp.size();i++){
		int x=allp[i];
		bitset<mid*2>fake,fakea;
		for(int i=0;i<x;i++){
			fake[i]=0;
		}
		for(int i=x;i<mid*2;i++){
			fake[i]=bt[i-x];
		}
		for(int i=0;i<mid*2-x;i++){
			fakea[i]=bt[i+x];
		}
		for(int i=mid*2-x;i<mid*2;i++){
			fakea[i]=0;
		}
		for(int i=0;i<mid*2;i++){
			if(fake[i]==1||fakea[i]==1){
				bt[i]=1;
			}
			else{
				bt[i]=0;
			}
		}
	}
	for(int i=mid-k+unnow;i<=mid+k+unnow;i++){
		if(bt[i]==1){
			cout<<"YES\n";
			exit(0);
		}
	}
	cout<<"NO\n";
	exit(0);
}
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>k;
	vis.resize(n*2+1);
	fa.resize(n+1),fb.resize(n+1);
	all.resize(n*2);
	for(int i=0;i<n*2;i++){
		cin>>all[i].first.first>>all[i].first.second>>all[i].second;
	}
	for(int i=0;i<2*n;i++){
		fa[all[i].first.first].insert(i);
		fb[all[i].first.second].insert(i);
	}
	for(int i=1;i<=n;i++){
		if((int)fa[i].size()==1){
			auto x=*(fa[i].begin());
			del(x,0);
		}
		if((int)fb[i].size()==1){
			auto x=*(fb[i].begin());
			del(x,1);
		}
	}
	for(int i=0;i<n*2;i++){
		if(vis[i]==0){
			bf.push_back(i);
			res=0;
			bfs(1);
			allp.push_back(abs(res));
		}
	}
	if((int)alla.size()!=n||(int)allb.size()!=n){
		cout<<"NO\n";
		exit(0);
	}
	solve();
}

• Subtask 1: 18 / 18
• Subtask 2: 0 / 30
• Subtask 3: 0 / 23
• Subtask 4: 0 / 29