Submission #1071028

#	Time	Username	Problem	Language	Result	Execution time	Memory
1071028		Mike_Vu	Harbingers (CEOI09_harbingers)	C++14	60 / 100	1059 ms	34384 KiB

harbingers

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double dou;
#define pii pair<int, int>
#define pb push_back
#define fi first
#define se second

bool maximize(ll &x, ll y ){
    if (x < y) {x = y; return true;};
    return false;
}
bool minimize(ll &x, ll y){
    if (x > y) {x = y; return true;}
    return false;
}

ll divi(ll x, ll y) {
    return x/y-(x%y&&(x^y)<0);
}

struct Line{
    ll m, b;
    Line(ll slope, ll intercept){
        m = slope;
        b = intercept;
    }
    ll cal(ll x) {
        return m*x+b;
    }
};
struct CHT{
    ll inter(Line a, Line b){
        return divi(b.b-a.b, a.m-b.m);
    }
    vector<pair<Line, int>> hull;
    void update(Line a, vector<pair<Line, int>> &temp) {
        while (!hull.empty() && hull.back().se >= inter(hull.back().fi, a)){
            temp.pb(hull.back());
            hull.pop_back();
        }
        if (hull.empty()) {
            hull.push_back({a, LLONG_MIN});
        }
        else {
            hull.push_back({a, inter(a, hull.back().fi)});
        }
    }
    void placeback(vector<pair<Line, int>> &temp) {
        hull.pop_back();
        for (int i = (int)temp.size()-1; i >= 0; i--){
            hull.pb(temp[i]);
        }
    }
    ll getval(ll x) {
        int k = 0;
        for (int i = (int)hull.size(); i; i >>= 1) {
            while (k+i < (int)hull.size() && hull[k+i].se < x) k += i;
        }
        return hull[k].fi.cal(x);
    }
} cht;

const int maxn = 1e5+5;
int n;
vector<pair<int, ll>> a[maxn];
ll b[maxn], s[maxn], dp[maxn], ps[maxn];

void dfs(int u, int p) {
    if (p > -1) {
        //cal
        dp[u] = s[u]+b[u]*ps[u]+cht.getval(b[u]);
    }
    vector<pair<Line, int>> temp; //temp
    cht.update(Line(-ps[u], dp[u]), temp);
    for (int i = 0; i < (int)a[u].size(); i++) {
        int v = a[u][i].fi;
        ll w = a[u][i].se;
        if (v == p) continue;
        ps[v] = ps[u] + w;
        dfs(v, u);
    }
    cht.placeback(temp);
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    #define task "harbingers"
    if (fopen(task".in", "r")){
        freopen(task".in", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    dp[1] = ps[1] = 0;
    cin >> n;
    for (int i= 1; i < n; i++) {
        int u, v;
        ll w;
        cin >> u >> v >> w;
        a[u].pb({v, w});
        a[v].pb({u, w});
    }
    for (int i = 2; i <= n; i++) {
        cin >> s[i] >> b[i];
    }
    dfs(1, -1);
    for (int i = 2; i <= n; i++) {
        cout << dp[i] << ' ';
    }
}

Compilation message (stderr)

harbingers.cpp: In function 'int main()':
harbingers.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen(task".in", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
harbingers.cpp:94:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 60 / 100