Submission #947806

#	Time	Username	Problem	Language	Result	Execution time	Memory
947806		pcc	Construction of Highway (JOI18_construction)	C++17	100 / 100	289 ms	87240 KiB

construction

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fs first
#define sc second
#define tiii tuple<int,int,int>
#define tlll tuple<ll,ll,ll>


const int mxn = 1e5+10;
vector<int> tree[mxn];
int link_top[mxn],sz[mxn],bs[mxn],idx[mxn],par[mxn],dep[mxn];
int N;
int arr[mxn];
vector<pii> req;
deque<tiii> dq[mxn];
int cnt = 0;

int dfs1(int now){
	sz[now] = 1;
	for(auto nxt:tree[now]){
		par[nxt] = now;
		dep[nxt] = dep[now]+1;
		sz[now] += dfs1(nxt);
		if(!bs[now]||sz[nxt]>sz[bs[now]])bs[now] = nxt;
	}
	return sz[now];
}

void dfs2(int now,int top){
	dq[top].push_back(tiii(dep[now],dep[now],arr[now]));
	link_top[now] = top;
	idx[now] = ++cnt;
	if(bs[now])dfs2(bs[now],top);
	for(auto nxt:tree[now]){
		if(nxt == bs[now])continue;
		dfs2(nxt,nxt);
	}
	return;
}

struct BIT{
	int bit[mxn];
	BIT(){
		memset(bit,0,sizeof(bit));
	}
	void modify(int p,int v){
		for(;p<mxn;p+=p&-p)bit[p] += v;
		return;
	}
	ll getval(int p){
		ll re = 0;
		for(;p>0;p-= p&-p)re += bit[p];
		return re;
	}
};
BIT bit;

ll get_inv(vector<pii> &v){
	ll re = 0;
	for(auto &i:v){
		re += 1ll*i.fs*bit.getval(i.sc-1);
		bit.modify(i.sc,i.fs);
	}
	for(auto &i:v){
		bit.modify(i.sc,-(bit.getval(i.sc)-bit.getval(i.sc-1)));
	}
	return re;
}

void calc(int a,int b){
	vector<pii> vv;
	int now = a;
	//cerr<<"CALC:"<<a<<','<<b<<":"<<endl;
	while(now){
		vector<pii> v;
		int tp = link_top[now];
		int st = get<0>(dq[tp].front());
		//cerr<<now<<' '<<tp<<":";for(auto &[a,b,c]:dq[tp])cerr<<a<<' '<<b<<' '<<c<<',';
		//cerr<<endl;
		while(!dq[tp].empty()){
			auto &[s,e,val] = dq[tp].front();
			if(s>dep[now])break;
			v.push_back(pii(min(e,dep[now])-s+1,val));
			if(e>dep[now]){
				s = dep[now]+1;
				break;
			}
			dq[tp].pop_front();
		}
		dq[tp].push_front(tiii(st,dep[now],arr[b]));
		now = par[tp];
		for(auto it = v.rbegin();it != v.rend();it++)vv.push_back(*it);
	}
	//cerr<<"V:";for(auto [a,b]:vv)cerr<<a<<' '<<b<<',';cerr<<endl;
	cout<<get_inv(vv)<<'\n';
	return;
}


vector<int> all;
int main(){
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	cin>>N;
	all.push_back(0);
	for(int i = 1;i<=N;i++){
		cin>>arr[i];
		all.push_back(arr[i]);
	}
	sort(all.begin(),all.end());all.resize(unique(all.begin(),all.end())-all.begin());
	for(int i = 1;i<=N;i++){
		arr[i] = lower_bound(all.begin(),all.end(),arr[i])-all.begin();
	}
	for(int i = 1;i<N;i++){
		int a,b;
		cin>>a>>b;
		tree[a].push_back(b);
		req.push_back({a,b});
	}
	dfs1(1);
	dfs2(1,1);
	for(auto &i:req)calc(i.fs,i.sc);
}

• Subtask 1: 7 / 7
• Subtask 2: 9 / 9
• Subtask 3: 84 / 84