Submission #1235324

#	Time	Username	Problem	Language	Result	Execution time	Memory
1235324		blackslex	Harbingers (CEOI09_harbingers)	C++20	0 / 100	78 ms	19272 KiB

harbingers

#include<bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;

const int N = 1e5 + 5;
int n, x, y, z, s[N], t[N], sz;
ll dp[N];
vector<pii> v[N];

struct line {
    ll m, c;
    line() : m(0), c(0) {}
    line(ll m, ll c) : m(m), c(c) {}
    ll get (ll x) {
        return m * x + c;
    }
    friend ld operator * (const line &l1, const line &l2) {
        return 1.l * (l2.c - l1.c) / 1.l * (l1.m - l2.m);
    }
} sk[N];

int add (line _l) {
    if (sz < 2) return sz;
    if (_l * sk[sz - 1] >= sk[sz - 1] * sk[sz - 2]) return sz;
    int l = 1, r = sz - 1;
    while (l < r) {
        int mid = (l + r) >> 1;
        if (_l * sk[mid] >= sk[mid] * sk[mid - 1]) r = mid;
        else l = mid + 1;
    }
    return l;
}

ll qr (ll x) {
    int l = 0, r = sz - 1;
    while (l < r) {
        int mid = (l + r) >> 1;
        if (sk[mid] * sk[mid + 1] >= x) r = mid;
        else l = mid + 1;
    }
    return sk[l].get(x);
}

void dfs (int cur, int par, ll dist){
    if (cur != 1) {
        dp[cur] = qr(t[cur]) + s[cur] + dist * t[cur];
    }
    line l(-dist, dp[cur]);
    int kk = add(l);
    int csz = sz, ccsz = kk;
    auto lk = sk[kk];
    sk[sz++] = l;
    // hull.add(-dist, dp[cur]);
    for (auto &[x, y]: v[cur]) {
        if (par == x) continue;
        dfs(x, cur, dist + y);
    }
    sk[ccsz] = lk;
    sz = csz;
}

int main() {
    scanf("%d", &n);
    for (int i = 1; i < n; i++) {
        scanf("%d %d %d", &x, &y, &z);
        v[x].emplace_back(y, z);
        v[y].emplace_back(x, z);
    }
    for (int i = 2; i <= n; i++) scanf("%d %d", &s[i], &t[i]);
    dp[1] = 0;
    dfs(1, 0, 0);
    for (int i = 2; i <= n; i++) printf("%lld ", dp[i]);
}

Compilation message (stderr)

harbingers.cpp: In function 'int main()':
harbingers.cpp:66:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
harbingers.cpp:68:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         scanf("%d %d %d", &x, &y, &z);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
harbingers.cpp:72:39: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |     for (int i = 2; i <= n; i++) scanf("%d %d", &s[i], &t[i]);
      |                                  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100