Submission #716578

#	Time	Username	Problem	Language	Result	Execution time	Memory
716578		guagua0407	Harbingers (CEOI09_harbingers)	C++17	20 / 100	128 ms	65536 KiB

harbingers

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#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 int mxn=1e5+5;
vector<pair<int,int>> adj[mxn];
ll S[mxn];
ll V[mxn];
line li[mxn];
ll depth[mxn];
ll dp[mxn];

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

bool check(int a,int b,int 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(int v,int p,deque<int> vec){
    int l=0,r=vec.size()-1;
    while(l<r){
        int 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]};
    while(vec.size()>1 and check(v,vec[0],vec[1])){
        vec.pop_front();
    }
    vec.push_front(v);
    for(auto u:adj[v]){
        if(u.f==p) continue;
        dfs(u.f,v,vec);
    }
    deque<int>().swap(vec);
}


int main() {_
    int n;
    cin>>n;
    for(int i=0;i<n-1;i++){
        int d,u,v;
        cin>>u>>v>>d;
        adj[u].push_back({v,d});
        adj[v].push_back({u,d});
    }
    for(int i=2;i<=n;i++){
        cin>>S[i]>>V[i];
    }
    dfs0(1,0);
    deque<int> tmp;
    tmp.push_back(0);
    dfs(1,0,tmp);
    for(int 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: 20 / 100