Submission #888138

#	Time	Username	Problem	Language	Result	Execution time	Memory
888138		Shayan86	Construction of Highway (JOI18_construction)	C++14	0 / 100	2 ms	6748 KiB

construction

#include <bits/stdc++.h>
using namespace std;

#pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// Ofast, O0, O1, O2, O3, unroll-loops, fast-math, trapv

typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;

#define Mp          make_pair
#define sep         ' '
#define endl        '\n'
#define F	        first
#define S	        second
#define pb          push_back
#define all(x)      (x).begin(),(x).end()
#define kill(res)	cout << res << '\n', exit(0);
#define set_dec(x)	cout << fixed << setprecision(x);
#define fast_io     ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io     freopen("input.txt", "r", stdin) ; freopen("output.txt", "w", stdout);

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll L = 19;
const ll sq = 1000;
const ll N = 1e5 + 50;
const ll Mod = 1e9 + 7;

ll n, c[N], par[N][L], h[N], mx[N];

vector<int> edge, adj[N];

void dfs(int v, int p = 0){
    par[v][0] = p;
    for(int i = 1; i < L; i++){
        if(!par[v][i-1]) break;
        par[v][i] = par[par[v][i-1]][i-1];
    }
    for(int u: adj[v]){
        h[u] = h[v] + 1; dfs(u, v);
    }
}

int getPar(int v, int k){
    for(int i = 0; i < L; i++){
        if(k >> i & 1) v = par[v][i];
    }
    return v;
}

int lca(int v, int u){
    if(h[v] < h[u]) swap(u, v);
    v = getPar(v, h[v] - h[u]);
    if(u == v) return v;

    for(int i = L-1; i >= 0; i--){
        if(par[v][i] != par[u][i]){
            v = par[v][i]; u = par[u][i];
        }
    }
    return par[v][0];
}

void prep(int v){
    for(int u: adj[v]){
        prep(u); mx[v] = max(mx[v], mx[u]);
    }
    if(mx[v]) c[v] = c[edge[mx[v]]];
}

vector<int> vec;
vector<pii> block;

int bit[N], m;

void upd(int x, int y){
    for(; x <= m; x += x & (-x)) bit[x] += y;
}

int get(int x){
    int out = 0;
    for(; x; x -= x & (-x)) out += bit[x];
    return out;
}

ll solve(){
    fill(bit, bit + N, 0);

    vec.clear();
    for(auto i: block) vec.pb(i.F);

    sort(all(vec)); vec.resize(unique(all(vec)) - vec.begin());
    m = vec.size();

    int sum = 0; ll res = 0;
    for(auto [x, y]: block){
        int id = lower_bound(all(vec), x) - vec.begin() + 1;
        res += (sum - get(id)); upd(id, y); sum += y;
    }
    return res;
}

int main(){
    fast_io;

    cin >> n;

    for(int i = 1; i <= n; i++) cin >> c[i];

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

    dfs(1);

    for(int i = 1; i < n; i++){
        block.clear(); 
        int tah = -1; v = edge[i];
        for(int j = i-1; j > 0; j--){
            u = lca(v, edge[j]);
            if(h[u] > tah){
                block.pb({c[edge[j]], h[u] - tah});
                tah = h[u];
            }
        }
        /*vec.clear();
        while(h[v] - 1 > tah){
            v = par[v][0]; vec.pb(c[v]);
        }
        reverse(all(vec));

        for(int j: vec) block.pb({j, 1});*/

        /*vec.clear();
        for(auto [x, y]: block) for(int j = 0; j < y; j++) vec.pb(x);

        ll res = 0;
        for(int j = 0; j < vec.size(); j++) for(int k = j+1; k < vec.size(); k++) if(vec[j] > vec[k]) res++;
        cout << res << endl;*/

        cout << solve() << endl;
/*
        if(i % sq == 0){
            fill(mx, mx + N, 0);
            for(int j = i; j > i - sq; j--) mx[edge[j]] = j;
            prep(1);
        }*/
    }

}

Compilation message (stderr)

construction.cpp: In function 'll solve()':
construction.cpp:98:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   98 |     for(auto [x, y]: block){
      |              ^

• Subtask 1: 0 / 7
• Subtask 2: 0 / 9
• Subtask 3: 0 / 84