Submission #879012

#	Time	Username	Problem	Language	Result	Execution time	Memory
879012		_anhxinloi_	Janjetina (COCI21_janjetina)	C++14	110 / 110	352 ms	59884 KiB

Main

#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second

using namespace std;

const int maxn = 2e5 + 5;
typedef pair<int, int> pii;

int n, k, pa[maxn], child[maxn], ans;
vector<pii> adj[maxn], g[maxn];
int bit[2*maxn];
bool check[maxn];

void update(int idx, int val){
    for(++idx; idx <= 100000; idx += idx&(-idx))
        bit[idx] += val;
}
int get(int idx){
    int ret = 0;
    for(++idx; idx > 0; idx -= idx&(-idx))
        ret += bit[idx];
    return ret;
}

int dfs_sz(int u, int par){
    child[u] = 1;
    for(auto z : adj[u]){
        auto [w, v] = z;
        if(v == par || check[v])
            continue;
        dfs_sz(v, u);
        child[u] += child[v];
    }
    return child[u];
}

//int centroid(int u, int par, int sz){
//    for(auto z : adj[u]){
//        auto [w, v] = z;
//        if(v == par || check[v])
//            continue;
//        if(child[v] * 2 >= sz)
//            return centroid(v, u, sz);
//    }
//    return u;
//}

int centroid(int v, int prt, int tot){
    for(auto u : adj[v])
        if(u.se != prt && !check[u.se] && child[u.se]*2 >= tot)
            return centroid(u.se, v, tot);
    return v;
}

void dfs_work(int u, int par, int val, int dist, int top){
    g[top].push_back(make_pair(val, dist));
    for(auto z : adj[u]){
        auto [w, v] = z;
        if(v == par || check[v])
            continue;
        dfs_work(v, u, max(val, w), dist+1, top);
    }
}

void build(int u, int par){
    int sz = dfs_sz(u, par);
    int center = centroid(u, par, sz);
//    cout << center << endl;
    pa[center] = u;

    vector<pii> vec = {};
    for(auto z : adj[center]){
        auto [w, v] = z;
        if(check[v])
            continue;
        dfs_work(v, center, w, 1, v);
        sort(g[v].begin(), g[v].end());

        for(auto z : g[v]){
            auto [val, dist] = z;
            int cur = val - dist - k;
//            cout << cur << endl;
            if(cur >= 0){
                ++ans;
                ans -= get(cur);
            }
            update(dist, 1);
        }

        for(auto z : g[v]){
            auto [val, dist] = z;
            update(dist, -1);
            vec.push_back(z);
        }
    }

    sort(vec.begin(), vec.end());
    for(auto z : vec){
        auto [val, dist] = z;
        int cur = val - dist - k;
        if(cur >= 0){
            ans += get(cur);
        }
        update(dist, 1);
    }

    for(auto z : vec){
        auto [val, dist] = z;
        update(dist, -1);
    }

    for(auto z : adj[center]){
        auto [w, v] = z;
        g[v].clear();
    }

    check[center] = true;
    for(auto z : adj[center]){
        auto [w, v] = z;
        if(!check[v])
            build(v, center);
    }
}

signed main(){
//    freopen("love.inp" , "r" , stdin);
//    freopen("love.out" , "w" , stdout);

    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    cin >> n >> k;
    for(int i=1 ; i<n ; ++i){
       int u, v, w;
       cin >> u >> v >> w;
       adj[u].push_back({w, v});
       adj[v].push_back({w, u});
    }

    build(1, -1);
    cout << ans * 2;
}

Compilation message (stderr)

Main.cpp: In function 'long long int dfs_sz(long long int, long long int)':
Main.cpp:30:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   30 |         auto [w, v] = z;
      |              ^
Main.cpp: In function 'void dfs_work(long long int, long long int, long long int, long long int, long long int)':
Main.cpp:60:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   60 |         auto [w, v] = z;
      |              ^
Main.cpp: In function 'void build(long long int, long long int)':
Main.cpp:75:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   75 |         auto [w, v] = z;
      |              ^
Main.cpp:82:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   82 |             auto [val, dist] = z;
      |                  ^
Main.cpp:93:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   93 |             auto [val, dist] = z;
      |                  ^
Main.cpp:101:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  101 |         auto [val, dist] = z;
      |              ^
Main.cpp:110:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  110 |         auto [val, dist] = z;
      |              ^
Main.cpp:115:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  115 |         auto [w, v] = z;
      |              ^
Main.cpp:121:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  121 |         auto [w, v] = z;
      |              ^

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