Submission #869151

#	Time	Username	Problem	Language	Result	Execution time	Memory
869151		sleepntsheep	Harbingers (CEOI09_harbingers)	C++17	0 / 100	92 ms	21584 KiB

harbingers

#include <cstdio>
#include <stack>
#include <cstring>
#include <cassert>
#include <string>
#include <deque>
#include <vector>
#include <map>
#include <queue>
#include <algorithm>
#include <iostream>
#include <utility>
using namespace std;
using ll = long long;
using ld = long double;
#define ShinLena cin.tie(nullptr)->sync_with_stdio(false)

#define N 100005
#define ALL(x) x.begin(), x.end()

struct line
{
    ll m, c;
    line(ll m, ll c) : m(m), c(c) {}
    line() : m(0), c(0) {}
    inline ll operator[](ll x) { return m*x+c; }
    inline ll intersect(line &l) { if (l.m==m) return 1e18; return (ll)(c-l.c)/(l.m-m); }
};

int n, s[N], v[N];
ll rt[N], dp[N];
vector<pair<int, int>> g[N];
line cht[N]; int sz;

inline int add(line k)
{
    if (!sz || sz && cht[sz].intersect(cht[sz-1]) < cht[sz-1].intersect(k)) return sz+1;
    int l = 1, r = sz, z = 0;
    for (; l <= r;)
    {
        int m = (l+r)/2;
        if (cht[m].m == k.m)
        {
            if (cht[m].c <= k.c) z = m, l = m + 1;
            else return 0;
        }
        else
        {
            if (cht[m].intersect(cht[m-1]) > cht[m-1].intersect(k)) z = m, l = m + 1;
            else r = m - 1;
        }
    }
    return z;
}

inline ll qry(ll x)
{
    if (!sz) return 0;
    int l = 0, r = sz - 1, z = sz;
    for (;l <= r;)
    {
        int m = (l+r)/2;
        if (cht[m].intersect(cht[m+1]) < x) l=m+1;
        else r=m-1, z = m;
    }
    return cht[z][x];
}

void dfs(int u, int p)
{
    int at, psz = sz;
    dp[u] = s[u] + 1ll*v[u]*rt[u] - qry(v[u]);
    dp[1] = 0;
    at = add(line{rt[u], -dp[u]});
    line overwrote = cht[at], nw {rt[u], -dp[u]};
    if (at) cht[at] = nw, sz = at;
    for (auto [w, v] : g[u]) if (v != p) rt[v] = rt[u] + w, dfs(v, u);
    if (at)
        sz = psz, cht[at] = overwrote;
}

int main()
{
    ShinLena;
    cin >> n;
    for (int u, v, w, i = 1; i < n; ++i) cin >> u >> v >> w, g[u].emplace_back(w, v), g[v].emplace_back(w, u);
    for (int i = 2; i <= n; ++i) cin >> s[i] >> v[i];
    dfs(1, 1);
    for (int i = 2; i <= n; ++i) cout << dp[i] << ' ';

    return 0;
}

Compilation message (stderr)

harbingers.cpp: In function 'int add(line)':
harbingers.cpp:37:19: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   37 |     if (!sz || sz && cht[sz].intersect(cht[sz-1]) < cht[sz-1].intersect(k)) return sz+1;
      |                ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100