Submission #717976

#	Time	Username	Problem	Language	Result	Execution time	Memory
717976		guagua0407	Harbingers (CEOI09_harbingers)	C++17	100 / 100	164 ms	21180 KiB

harbingers

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<ll,ll>
#define f first
#define s second
#define all(x) x.begin(),x.end() 
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

struct line{
    ll a,b;
    ll operator()(const ll x){
        return a*x+b;
    }
};

const ll mxn=1e5+5;
vector<pair<ll,ll>> adj[mxn];
ll S[mxn];
ll V[mxn];
line li[mxn];
ll depth[mxn];
ll dp[mxn];
int vec[mxn];
int cur_size=1;

void dfs0(ll v,ll p){
    for(auto u:adj[v]){
        if(u.f==p) continue;
        depth[u.f]=depth[v]+u.s;
        dfs0(u.f,v);
    }
}

bool check(ll a,ll b,ll c){
    line l1=li[a];
    line l2=li[b];
    line l3=li[c];
    return (long double)(l2.b-l3.b)/(l3.a-l2.a)<(long double)(l1.b-l2.b)/(l2.a-l1.a);
}

void dfs(ll v,ll p){
    ll l=0,r=cur_size-1;
    while(l<r){
        ll mid=(l+r)/2;
        if(li[vec[mid]](V[v])<=li[vec[mid+1]](V[v])){
            r=mid;
        }
        else{
            l=mid+1;
        }
    }
    dp[v]=S[v]+depth[v]*V[v]+li[vec[l]](V[v]);
    li[v]={-depth[v],dp[v]};
    l=0,r=cur_size-1;
    while(l<r){
        ll mid=(l+r)/2;
        if(check(vec[mid],vec[mid+1],v)){
            r=mid;
        }
        else{
            l=mid+1;
        }
    }
    int prv_size=cur_size;
    int prv_index=vec[l+1];
    cur_size=l+2;
    vec[l+1]=v;
    for(auto u:adj[v]){
        if(u.f==p) continue;
        dfs(u.f,v);
    }
    cur_size=prv_size;
    vec[l+1]=prv_index;
} 

int main() {_
    ll n;
    cin>>n;
    for(ll i=0;i<n-1;i++){
        ll d,u,v;
        cin>>u>>v>>d;
        adj[u].push_back({v,d});
        adj[v].push_back({u,d});
    }
    for(ll i=2;i<=n;i++){
        cin>>S[i]>>V[i];
    }
    dfs0(1,0);
    vec[0]=0;
    dfs(1,0);
    for(ll i=2;i<=n;i++){
        cout<<dp[i]<<' ';
    }
    return 0;
}
//maybe its multiset not set

Compilation message (stderr)

harbingers.cpp: In function 'void setIO(std::string)':
harbingers.cpp:12:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
harbingers.cpp:13:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100