Submission #929056

#	Time	Username	Problem	Language	Result	Execution time	Memory
929056		Amirreza_Fakhri	Janjetina (COCI21_janjetina)	C++17	110 / 110	303 ms	17952 KiB

Main

// In the name of the God
#include <bits/stdc++.h>
#define ll long long
#define int long long
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define pii pair <int, int>
#define smin(x, y) (x) = min((x), (y))
#define smax(x, y) (x) = max((x), (y))
#define all(x) (x).begin(), (x).end()
using namespace std;

const int inf = 1e9+7;
const int mod = 998244353;
const int maxn = 1e5+5;

int n, k, sz[maxn], fen[maxn];
bool mark[maxn];
vector <pii> adj[maxn], vec1, vec2;

void dfs1(int v, int p) {
    sz[v] = 1;
    for (pii e : adj[v]) {
        int u = e.F;
        if (!mark[u] and u != p) {
            dfs1(u, v); sz[v] += sz[u];
        }
    }
}

int fcen(int v, int p, int s) {
    for (pii e : adj[v]) {
        int u = e.F;
        if (!mark[u] and u != p and sz[u]*2 > s) return fcen(u, v, s);
    }
    return v;
}

void dfs2(int v, int p, int mx, int h) {
    vec1.pb(mp(mx, h)), vec2.pb(mp(mx, h));
    for (pii e : adj[v]) {
        int u = e.F;
        if (!mark[u] and u != p) dfs2(u, v, max(mx, e.S), h+1);
    }
}

void upd(int i, int x) {
    i++;
    for (; i <= n; i += i&(-i)) fen[i] += x;
}

int get(int i) {
    i++;
    int ans = 0;
    for (; i; i -= i&(-i)) ans += fen[i] ;
    return ans;
}

int relax(vector <pii> &vec) {
    int res = 0;
    sort(all(vec));
    for (pii p : vec) {
        int j = p.F-k-p.S;
        if (j >= 0) res += get(min(j, n-1));
        upd(p.S, 1);
    }
    for (pii p : vec) upd(p.S, -1);
    vec.clear();
    return res;
}

int cen(int v) {
    dfs1(v, v);
    v = fcen(v, v, sz[v]);
    int ans = 0;
    vec2.pb(mp(0, 0));
    for (pii e : adj[v]) {
        int u = e.F;
        if (!mark[u]) {
            dfs2(u, v, e.S, 1);
            ans -= relax(vec1);
        }
    }
    ans += relax(vec2);
    mark[v] = 1;
    for (pii e : adj[v]) {
        int u = e.F;
        if (!mark[u]) ans += cen(u);
    }
    return ans;
}

int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> k;
    for (int i = 1; i < n; i++) {
        int v, u, w; cin >> v >> u >> w;
        adj[--v].pb(mp(--u, w));
        adj[u].pb(mp(v, w));
    }
    cout << cen(0)*2 << '\n';
    return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 60 / 60