Submission #1127216

#	Time	Username	Problem	Language	Result	Execution time	Memory
1127216		steveonalex	Janjetina (COCI21_janjetina)	C++20	110 / 110	242 ms	17740 KiB

Main

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()

ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}

ll gcd(ll a, ll b){
    while(a > 0 && b > 0){
        if (a > b) a %= b;
        else b %= a;
    }
    return a + b;
}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ll mask){return __builtin_ctzll(mask);}
int logOf(ll mask){return __lg(mask);}

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}

template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }

template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }

template <class T>
    void printArr(T& container, string separator = " ", string finish = "\n"){
        for(auto item: container) cout << item << separator;
        cout << finish;
    }


template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }


struct FenwickTree{
    int n;
    vector<ll> a;

    FenwickTree(int _n){
        n = _n;
        a.resize(n+1);
    }

    void update(int i, ll v){
        while(i <= n){
            a[i] += v;
            i += LASTBIT(i);
        }
    }

    ll get(int i){
        ll ans = 0;
        while(i > 0){
            ans += a[i];
            i -= LASTBIT(i);
        }
        return ans;
    }

    ll get(int l, int r){return get(r) - get(l-1);}

    int binary_lift(ll x){
        int p = MASK(logOf(n)), idx =0;
        while(p > 0){
            if (idx + p <= n && x > a[idx + p]){
                idx += p;
                x -= a[idx];
            }
            p >>= 1;
        }
        return idx + 1;
    }
};

const int N = 1e5 + 69;
int n, k;
vector<pair<int, int>> graph[N];
int weight[N];
ll ans = 0;

ll count_pair(vector<pair<int, int>> a){
    if (a.size() == 1) return 0;
    int ma = 0;
    for(pair<int, int> i: a) maximize(ma, i.second);

    FenwickTree bit(ma + 1);
    sort(ALL(a));
    ll ans = 0;
    for(pair<int, int> i: a){
        int cur = i.first - k - i.second;
        if (cur >= 0) ans += bit.get(min(cur + 1, ma + 1));
        bit.update(i.second + 1, 1);
    }

    return ans;
}

namespace CentroidDecomposition{
    bool banned[N];
    int sz[N];
    int h[N], ma[N];

    void find_sz(int u, int p){
        sz[u] = 1;
        for(pair<int, int> v: graph[u]) if (v.first != p && !banned[v.second]){
            find_sz(v.first, u);
            sz[u] += sz[v.first];
        }
    }

    int find_centroid(int u){
        for(pair<int, int> v: graph[u]) if (!banned[v.second]) {
            if (sz[v.first] * 2 > sz[u]) {
                sz[u] -= sz[v.first];
                sz[v.first] += sz[u];

                return find_centroid(v.first);
            }
        }
        return u;
    }

    void dfs(int u, int p){
        for(pair<int, int> v: graph[u]) if (v.first != p && !banned[v.second]){
            h[v.first] = h[u] + 1;
            ma[v.first] = max(ma[u], weight[v.second]);
            dfs(v.first, u);
        }
    }

    void get_point(int u, int p, vector<pair<int, int>> &skr){
        skr.push_back({ma[u], h[u]});
        for(pair<int, int> v: graph[u]) if (v.first != p && !banned[v.second]){
            get_point(v.first, u, skr);
        }
    }

    void go(int u, int layer){
        find_sz(u, 0);
        u = find_centroid(u);

        h[u] = 0, ma[u] = 0;
        dfs(u, 0);

        vector<vector<pair<int, int>>> ski;
        vector<pair<int, int>> tot;
        tot.push_back({0, 0});
        for(pair<int, int> v: graph[u]) if (!banned[v.second]){
            vector<pair<int, int>> skr;
            get_point(v.first, u, skr);
            for(pair<int, int> j: skr) tot.push_back(j);
            ski.push_back(skr);
        }
        // cout << "->> Node: " << u << "\n";
        // for(pair<int, int> j: tot) cout << j.first << " " << j.second << "\n";
        // cout << "Plus: " << count_pair(tot) << "\n";
        ans += count_pair(tot);
        for(auto j: ski){
            ans -= count_pair(j);
        }

        for(pair<int, int> v: graph[u]) if (!banned[v.second]){
            banned[v.second] = true;
            go(v.first, layer + 1);
        }
    }
}

void solve(){
    cin >> n >> k;
    for(int i = 1; i < n; ++i){
        int u, v; cin >> u >> v >> weight[i];
        graph[u].push_back({v, i});
        graph[v].push_back({u, i});
    }

    CentroidDecomposition::go(1, 0);
    cout << ans * 2 << "\n";
}

int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    clock_t start = clock();

    solve();


    cerr << "Time elapsed: " << clock() - start << "ms!\n";
    return 0;
}

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