oj.uz

Submission #474817

# Submission time Handle Problem Language Result Execution time Memory
474817 2021-09-20T01:31:46 Z aniervs Harbingers (CEOI09_harbingers) C++17
60 / 100
 1000 ms 21972 KB 
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const int maxn = (int)2e5 + 5;

typedef pair<ll,ll> point;
#define x first
#define y second
point operator +(const point &a, const point &b){ return {a.x + b.x, a.y + b.y}; }
point operator -(const point &a, const point &b){ return {a.x - b.x, a.y - b.y}; }
ll cross(const point &a, const point &b){ return a.x * b.y  - a.y * b.x; }
ll area2(const point &a, const point &b, const point &c){ return cross(b - a, c - a); }

struct hull : vector<point>{
    void add_point(const point &p){ // p is greater than all the previous ones
        while(size() > 1 and area2(at(size()-2), at(size()-1), p) >= 0)
            pop_back();
        push_back(p);
    }

    ll max_dot(const ll &x){
        int l = 0, r = (int)size() - 1;

        while(l < r){
            int mid = (l + r)>>1;
            if(at(mid).x * x + at(mid).y <= at(mid + 1).x * x + at(mid + 1).y)
                l = mid + 1;
            else
                r = mid;
        }

        return at(l).x * x + at(l).y;
    }

};

vector<pair<int,int>> G[maxn];
ll speed[maxn], start[maxn], dp[maxn], sumW[maxn];
int n, sz[maxn];

void dfs(int u, int p){
    sz[u] = 1;
    for(auto [v, w]:G[u]){
        if(v == p)
            continue;
        sumW[v] = sumW[u] + w;
        dfs(v, u);
        sz[u] += sz[v];
    }
}


vector<hull> lights;
hull heavy;

void dfsHLD(int u, int p){

    if(u != 1){
        dp[u] = -1e18;
        for(int i = 0; i < (int)lights.size(); i++)
            dp[u] = max(dp[u], lights[i].max_dot(speed[u]));

        if(!heavy.empty())
            dp[u] = max(dp[u], heavy.max_dot(speed[u]));
        dp[u] = sumW[u] * speed[u] + start[u] - dp[u];
    }

    heavy.add_point({sumW[u], -dp[u]});
    lights.push_back(heavy);

    int bigChild = -1;
    for(auto [v, _]:G[u])
        if(v != p and (bigChild == -1 or sz[bigChild] < sz[v]))
            bigChild = v;
        
    for(auto [v, w]:G[u])
        if(v != bigChild and v != p){
            heavy.clear();
            dfsHLD(v, u);
        }
    heavy = lights.back();
    lights.pop_back();

    if(bigChild != -1)
        dfsHLD(bigChild, u);
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);

    cin >> n;
    for(int i = 1; i < n; i++){
        int u, v, w;
        cin >> u >> v >> w;
        G[u].push_back({v, w});
        G[v].push_back({u, w});
    }

    for(int i = 2; i <= n; i++)
        cin >> start[i] >> speed[i];
    
    dfs(1,-1);

    dfsHLD(1,-1);

    for(int i = 2; i <= n; i++)
        cout << dp[i] << ' ';   
    
    return 0;
}

Subtask #1
60.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 6 ms 5412 KB Output is correct
3 Correct 247 ms 13024 KB Output is correct
4 Execution timed out 1086 ms 16064 KB Time limit exceeded
5 Correct 99 ms 19184 KB Output is correct
6 Correct 131 ms 21972 KB Output is correct
7 Correct 75 ms 14316 KB Output is correct
8 Execution timed out 1082 ms 18008 KB Time limit exceeded
9 Execution timed out 1078 ms 20004 KB Time limit exceeded
10 Execution timed out 1084 ms 19224 KB Time limit exceeded