Submission #699006

#	Time	Username	Problem	Language	Result	Execution time	Memory
699006		Baytoro	Harbingers (CEOI09_harbingers)	C++17	100 / 100	121 ms	24508 KiB

harbingers

#include <bits/stdc++.h>
using namespace std;
#define ios ios::sync_with_stdio(false); cin.tie(NULL);cout.tie(NULL);
#define pb push_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define fr first
#define sc second
#define endl '\n'
#define int long long
#define ll long long
void fopn(string name){
	freopen((name+".in").c_str(),"r",stdin);
	freopen((name+".out").c_str(),"w",stdout);
}
const ll INF=1e18,mod=1e9+7;
const int N=1e5+5;
struct line{
	int m,b;
	int operator *(int x){
		return m*x+b;
	}
	int operator ^(line x){
		return ceil((b-x.b)/(x.m-m));
	}
};
int cnt=0;
line L[N];
vector<pair<int,int>> g[N];
int dp[N],v[N],s[N];
int query(int x){
	int l=0,r=cnt-1;
	while(l<r){
		int md=(l+r)/2;
		if((L[md]^L[md+1])<x) l=md+1;
		else r=md;
	}
	return L[l]*x;
}
int remo(line ln){
	if(cnt<2 || (ln^L[cnt-1])>=(L[cnt-1]^L[cnt-2])){
		return cnt;
	}
	int l=1,r=cnt-1;
	while(l<r){
		int md=(l+r)/2;
		if((ln^L[md])<(L[md]^L[md-1])) r=md;
		else l=md+1;
	}
	return l;
}
void dfs(int x, int par, int d){
	int mx=0,pos=0;
	line ln;
	if(x==1){
		dp[x]=0;
		L[cnt++]={0,0};
	}
	else{
		dp[x]=query(v[x])+(d*v[x]+s[x]);
		line l={-d,dp[x]};
		mx=cnt;
		pos=cnt=remo(l);
		ln=L[cnt];
		L[cnt++]=l;
	}
	for(auto it: g[x]){
		if(it.fr!=par) dfs(it.fr,x,d+it.sc);
	}
	if(x!=1) cnt=mx,L[pos]=ln;
}
void solve(){
	int n;cin>>n;
	for(int i=1;i<n;i++){
		int a,b,c;
		cin>>a>>b>>c;
		g[a].pb({b,c});
		g[b].pb({a,c});
	}
	for(int i=2;i<=n;i++)
		cin>>s[i]>>v[i];
	dfs(1,0,0);
	for(int i=2;i<=n;i++)
		cout<<dp[i]<<' ';
	//convex hull trick
}
main(){
	ios;
	int T=1;
	//cin>>T;
	while(T--){
		solve();
	}
}

Compilation message (stderr)

harbingers.cpp:87:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   87 | main(){
      | ^~~~
harbingers.cpp: In function 'void fopn(std::string)':
harbingers.cpp:13:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |  freopen((name+".in").c_str(),"r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
harbingers.cpp:14:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |  freopen((name+".out").c_str(),"w",stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100