Submission #406324

#	Time	Username	Problem	Language	Result	Execution time	Memory
406324		codebuster_10	Tug of War (BOI15_tug)	C++17	100 / 100	738 ms	37580 KiB

tug

#include <bits/stdc++.h>
 
using namespace std ;
 
#define int int64_t //be careful about this 
#define endl "\n"
#define f(i,a,b) for(int i=int(a);i<int(b);++i)
 
#define pr pair
#define ar array
#define fr first
#define sc second
#define vt vector
#define pb push_back
#define eb emplace_back
#define LB lower_bound  
#define UB upper_bound
#define PQ priority_queue
 
#define sz(x) ((int)(x).size())
#define all(a) (a).begin(),(a).end()
#define allr(a) (a).rbegin(),(a).rend()
#define mem0(a) memset(a, 0, sizeof(a))
#define mem1(a) memset(a, -1, sizeof(a))
 
template<class A> void rd(vt<A>& v);
template<class T> void rd(T& x){ cin >> x; }
template<class H, class... T> void rd(H& h, T&... t) { rd(h) ; rd(t...) ;}
template<class A> void rd(vt<A>& x) { for(auto& a : x) rd(a) ;}
 
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
 
template<typename T>
void __p(T a) {
  cout<<a; 
}
template<typename T, typename F>
void __p(pair<T, F> a) {
  cout<<"{";
  __p(a.first);
  cout<<",";
  __p(a.second);
  cout<<"}\n"; 
}
template<typename T>
void __p(std::vector<T> a) {
  cout<<"{";
  for(auto it=a.begin(); it<a.end(); it++)
    __p(*it),cout<<",}\n"[it+1==a.end()]; 
}
template<typename T, typename ...Arg>
void __p(T a1, Arg ...a) {
  __p(a1);
  __p(a...);
}
template<typename Arg1>
void __f(const char *name, Arg1 &&arg1) {
  cout<<name<<" : ";
  __p(arg1);
  cout<<endl;
}
template<typename Arg1, typename ... Args>
void __f(const char *names, Arg1 &&arg1, Args &&... args) {
  int bracket=0,i=0;
  for(;; i++)
    if(names[i]==','&&bracket==0)
      break;
    else if(names[i]=='(')
      bracket++;
    else if(names[i]==')')
      bracket--;
  const char *comma=names+i;
  cout.write(names,comma-names)<<" : ";
  __p(arg1);
  cout<<" | ";
  __f(comma+1,args...);
}
 
void setIO(string s = "") {
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); 
  cin.exceptions(cin.failbit); 
	cout.precision(15);	cout << fixed;
  #ifdef ONLINE_JUDGE
  if(sz(s)){
  	freopen((s+".in").c_str(),"r",stdin);
  	freopen((s+".out").c_str(),"w",stdout);
  }
  #define __f(...) 0
  #endif
}
 
void err(bool flag){cout << (flag?"YES":"NO"); exit(0);}
 
const int MAX_N = 2 * 300000 + 1;
multiset<pr<int,int>> g[MAX_N];
vt<bool> vis(MAX_N,false);
bitset<MAX_N> is;
int tot = 0;
 
void dfs(int i) {
	vis[i] = true;
	if (!sz(g[i])) return;
	auto [nxt,cost] = *g[i].begin();
	tot += cost;
	if (!vis[nxt]) {
		g[nxt].erase(g[nxt].find({i, -cost}));
		g[i].clear();
		dfs(nxt);
	}
}
 
 
signed main(){
  setIO() ;
	int n,k; rd(n,k);
	f(id,0,2*n){
		int l,r,s; rd(l,r,s);
		--l,--r;
		g[l].insert({r+n,s});
		g[r+n].insert({l,-s});
	}
	// keep removing those with degree one.
	queue<int> q;
	f(i,0,2*n){
		if(sz(g[i]) == 1) q.push(i);
		else if(sz(g[i]) == 0) err(0);
	}
	
	while(sz(q)){
		int now = q.front(); q.pop();
		if(!sz(g[now])) err(0);
		auto [nxt,cost] = *g[now].begin();
		tot += cost;
		g[now].clear();
		g[nxt].erase(g[nxt].find({now,-cost}));
		if(sz(g[nxt]) == 1) q.push(nxt);
	}
	
	vt<int> W;
	if(tot) W.pb(abs(tot));
	
	
	f(i,0,2*n) if(!vis[i] && sz(g[i])){
		tot = 0;
		g[i].erase(g[i].begin());
		dfs(i);
		if(tot) W.pb(abs(tot));
	}
	
	int sum = accumulate(all(W),0);
	is[0] = true;
	for(auto i : W) is |= (is << i);
	f(i,0,MAX_N){
		if(abs(sum - 2*i) <= k && is[i]) err(1);
	}
	err(0);
	
}

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