Submission #253968

#	Time	Username	Problem	Language	Result	Execution time	Memory
253968		errorgorn	Fireworks (APIO16_fireworks)	C++14	7 / 100	5 ms	7424 KiB

fireworks

//雪花飄飄北風嘯嘯
//天地一片蒼茫

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl;

#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()

ll MAX(ll a){return a;}
ll MIN(ll a){return a;}
template<typename... Args>
ll MAX(ll a,Args... args){return max(a,MAX(args...));}
template<typename... Args>
ll MIN(ll a,Args... args){return min(a,MIN(args...));}

#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

int n,m;
vector<ii> al[300005];

struct dat{
	ll l,r,h;
	
	dat(){
		l=r=h=0;
	}
};

dat dfs(int i){
	dat res=dat();
	
	if (n<i) return res;
	
	vector<ll> pos;
	vector<dat> dats;
	for (auto &it:al[i]){
		auto temp=dfs(it.fi);
		temp.l+=it.se,temp.r+=it.se;
		pos.push_back(temp.l);
		pos.push_back(temp.r);
		dats.push_back(temp);
	}
	
	sort(all(pos));
	
	int idx=sz(pos)/2;
	res.l=pos[idx-1],res.r=pos[idx];
	
	for (auto &it:dats){
		if (res.l<it.l) res.h+=it.l-res.l;
		else if (it.r<res.l) res.h+=res.l-it.r;
		res.h+=it.h;
	}
	
	//cout<<i<<" "<<res.l<<" "<<res.r<<" "<<res.h<<endl;
	return res;
}

int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	cin>>n>>m;
	
	int a,b;
	rep(x,2,n+m+1){
		cin>>a>>b;
		al[a].push_back(ii(x,b));
	}
	
	cout<<dfs(1).h<<endl;
}

• Subtask 1: 7 / 7
• Subtask 2: 0 / 19
• Subtask 3: 0 / 29
• Subtask 4: 0 / 45