Submission #1209220

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209220		russvn123	Harbingers (CEOI09_harbingers)	C++20	100 / 100	68 ms	19880 KiB

harbingers

#include <bits/stdc++.h>
#define int long long
using namespace std;
typedef long long ll;

typedef pair<int, int> Line;
#define X first
#define Y second
const int N = 1e5 + 9;
const ll INF = (ll)1e18;

struct operation {
    int pos, top;
    Line overwrite;
    operation(int _p, int _t, Line _o) {
        pos = _p; top = _t; overwrite = _o;
    }
};
vector<operation> undoLst;
Line lines[N];
int n, top;

ll eval(Line line, ll x) { return line.X * x + line.Y; }
bool bad(Line a, Line b, Line c) {
    return (double)(b.Y - a.Y) / (a.X - b.X) >= (double)(c.Y - a.Y) / (a.X - c.X);
}

ll getMin(ll coord) {
    int l = 0, r = top - 1; ll ans = eval(lines[l], coord);
    while (l < r) {
        int mid = l + r >> 1;
        ll x = eval(lines[mid], coord);
        ll y = eval(lines[mid + 1], coord);
        if (x > y) l = mid + 1; else r = mid;
        ans = min(ans, min(x, y));
    }
    return ans;
}

bool insertLine(Line newLine) {
    //cout<<newLine.first<<' '<<newLine.second<<endl;
    int l = 1, r = top - 1, k = top;
    while (l <= r) {
        int mid = l + r >> 1;
        if (bad(lines[mid - 1], lines[mid], newLine)) {
            k = mid; r = mid - 1;
        }
        else l = mid + 1;
    }
    undoLst.push_back(operation(k, top, lines[k]));
    top = k + 1;
    lines[k] = newLine;
    return true;
}

void undo() {
    operation ope = undoLst.back(); undoLst.pop_back();
    top = ope.top; lines[ope.pos] = ope.overwrite;
}

ll f[N], S[N], V[N], d[N];
vector<Line> a[N];

void dfs(int u, int par) {
    if (u > 1)
    {
        f[u] = getMin(V[u]) + S[u] + V[u] * d[u];
        //cout<<u<<' '<<getMin(V[u])<<endl;
    }
    //cout<<u<<' '<<-d[u]<<' '<<(int)f[u]<<endl;
    insertLine(make_pair(-d[u], f[u]));
    for (vector<Line>::iterator it = a[u].begin(); it != a[u].end(); ++it) {
        int v = it->X;
        int uv = it->Y;
        if (v == par) continue;
        d[v] = d[u] + uv;
        dfs(v, u);
    }
    undo();
}

int32_t main() {
    cin.tie(NULL)->sync_with_stdio(false);
    cin >> n;
    for (int i = 1; i < n; ++i) {
        int u, v, c;
        cin >> u >> v >> c;
        a[u].emplace_back(v, c);
        a[v].emplace_back(u, c);
    }
    for (int i = 2; i <= n; ++i) cin >> S[i] >> V[i];
    dfs(1, 0);
    for (int i = 2; i <= n; ++i) cout << f[i] << ' ';
}

• Subtask 1: 100 / 100