Submission #608640

#	Time	Username	Problem	Language	Result	Execution time	Memory
608640		Do_you_copy	Harbingers (CEOI09_harbingers)	C++17	50 / 100	125 ms	21132 KiB

harbingers

#include <bits/stdc++.h>
#define taskname "test"
#define fi first
#define se second
#define pb push_back
#define faster ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
using ll = long long;
using ull = unsigned ll;
using ld = long double;
using pii = pair <int, int>;
using pil = pair <int, ll>;
using pli = pair <ll, int>;
using pll = pair <ll, ll>;
mt19937 Rand(chrono::steady_clock::now().time_since_epoch().count());

ll min(const ll &a, const ll &b){
    return (a < b) ? a : b;
}

ll max(const ll &a, const ll &b){
    return (a > b) ? a : b;
}

//const ll Mod = 1000000007;
//const ll Mod2 = 999999999989;
//only use when required
const int maxN = 1e5 + 1;

int n;
vector <pii> adj[maxN];
int s[maxN], v[maxN];
pll cht[maxN];
int sz = 0;
int dp[maxN];

inline ld intersect(pll l, pll r){
    return ld(r.se - l.se) / ld(l.fi - r.fi);
}

ll get(ll x){
     int l = 0, r = sz - 1;
     while (l < r){
        int mid = (l + r) / 2;
        if (intersect(cht[mid], cht[mid + 1]) < x) l = mid + 1;
        else r = mid;
     }
     return cht[l].fi * x + cht[l].se;
}

int update(pll line){
    if (sz < 2 || intersect(line, cht[sz - 1]) >= intersect(cht[sz - 1], cht[sz - 2])){
        return sz;
    }
    int l = 1, r = sz - 1;
    while (l < r){
        int mid = (l + r) / 2;
        if (intersect(line, cht[mid]) < intersect(cht[mid], cht[mid - 1])) r = mid;
        else l = mid + 1;
    }
    return l;
}

void dfs(int u, int p, ll dis = 0){
    int pre_size, pre_pos;
    pll pre_line;
    if (u == 1){
        cht[sz++] = {0, 0};
    }
    else{
        dp[u] = get(v[u]) + dis * v[u] + s[u];
        pll line = {-dis, dp[u]};
        pre_size = sz;
        pre_pos = sz = update(line);
        pre_line = cht[pre_pos];
        cht[sz++] = line;
    }
    for (const auto &i: adj[u]){
        if (i.fi == p) continue;
        dfs(i.fi, u, i.se + dis);
    }
    if (u != 1){
        sz = pre_size;
        cht[pre_pos] = pre_line;
    }
}

void Init(){
    cin >> n;
    for (int i = 1; i < n; ++i){
        int u, v, w;
        cin >> u >> v >> w;
        adj[v].pb({u, w});
        adj[u].pb({v, w});
    }
    for (int i = 2; i <= n; ++i){
        cin >> s[i] >> v[i];
    }
    dfs(1, 0);
    for (int i = 2; i <= n; ++i) cout << dp[i] << " ";
}


int main(){
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        //freopen(taskname".out", "w", stdout);
    }
    faster;
    ll tt = 1;
    //cin >> tt;
    while (tt--){
        Init();
    }
}

Compilation message (stderr)

harbingers.cpp: In function 'int main()':
harbingers.cpp:106:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 50 / 100