Submission #816463

#	Time	Username	Problem	Language	Result	Execution time	Memory
816463		Jarif_Rahman	Highway Tolls (IOI18_highway)	C++17	51 / 100	214 ms	262144 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

int n, m;
ll A, B;
vector<vector<pair<int, int>>> graph;
vector<int> depth, p, pe;

ll def;

void dfs(int nd, int dad, int dad_edge, int d){
    p[nd] = dad;
    depth[nd] = d;
    pe[nd] = dad_edge;
    for(auto [x, i]: graph[nd]) if(x != dad) dfs(x, nd, i, d+1);
}

int find_node(int root){
    dfs(root, -1, -1, 0);
    vector<int> o(n);
    for(int i = 0; i < n; i++) o[i] = i;
    sort(o.begin(), o.end(), [&](int a, int b){
        return depth[a] > depth[b];
    });

    ll def = ask(vector<int>(m, 0));

    int a = 0, b = n-1;
    while(a < b){
        int md = (a+b)/2;
        vector<int> w(m, 0);
        for(int i = 0; i <= md; i++) if(pe[o[i]] != -1) w[pe[o[i]]] = 1;
        ll x = ask(w);
        if(x > def) b = md;
        else a = md+1;
    }

    return o[a];
}

void find_pair(int _n, vector<int> U, vector<int> V, int _A, int _B){
    swap(n, _n);
    m = U.size();
    A = _A, B = _B;
    graph.resize(n);
    depth.resize(n);
    p.resize(n);
    pe.resize(n, -1);

    for(int i = 0; i < m; i++){
        graph[U[i]].pb({V[i], i});
        graph[V[i]].pb({U[i], i});
    }

    def = ask(vector<int>(m, 0));

    int s = find_node(0);
    int t = find_node(s);
    answer(s, t);
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31