Submission #492158

#	Time	Username	Problem	Language	Result	Execution time	Memory
492158		couplefire	Harbingers (CEOI09_harbingers)	C++17	100 / 100	121 ms	23676 KiB

harbingers

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define pii pair<int, int>
#define f first
#define s second

const int N = 100005;

struct line{
    int m, b; line(){}
    line(int _m, int _b): m(_m), b(_b){}
    ld isect(line o){return ((ld)o.b-b)/((ld)m-o.m);}
    int eval(int x){return m*x+b;}
} st[N]; int top;

int query(int x){
    int lo = 1, hi = top;
    while(lo<hi){
        int mid = lo+(hi-lo+1)/2;
        if(st[mid].isect(st[mid-1])<=(ld)x) lo = mid;
        else hi = mid-1;
    } return st[lo].eval(x);
}

int add(line l){
    int lo = 1, hi = top+1;
    while(lo<hi){
        int mid = lo+(hi-lo)/2;
        if(mid>1 && st[mid].isect(l)<=st[mid].isect(st[mid-1])) hi = mid;
        else lo = mid+1;
    } return lo;
}

int n, s[N], w[N], d[N], dp[N];
vector<pii> adj[N];

void dfs(int v, int p){
    line pline; int ptop = 0;
    if(!v) dp[v] = 0, st[++top] = line(0, 0);
    else{
        dp[v] = query(s[v])+d[v]*s[v]+w[v];
        line todo = line(-d[v], dp[v]);
        int pos = add(todo);
        pline = st[pos]; ptop = top;
        st[top = pos] = todo;
    }
    for(auto [u, x] : adj[v])
        if(u!=p) d[u] = d[v]+x, dfs(u, v);
    if(v) st[top] = pline, top = ptop;
}

signed main(){
    // freopen("a.in", "r", stdin);
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    for(int i = 0; i<n-1; ++i){
        int u, v, d; cin >> u >> v >> d;
        --u; --v;
        adj[u].push_back({v, d});
        adj[v].push_back({u, d});
    }
    for(int i = 1; i<n; ++i)
        cin >> w[i] >> s[i];
    dfs(0, 0);
    for(int i = 1; i<n; ++i)
        cout << dp[i] << ' ';
    cout << '\n';
}

• Subtask 1: 100 / 100