Submission #818374

#	Time	Username	Problem	Language	Result	Execution time	Memory
818374		Jarif_Rahman	Highway Tolls (IOI18_highway)	C++17	90 / 100	176 ms	11056 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;
 
ll def;
 
int find_node(int root){
    vector<int> dis(n, -1);
    queue<int> Q;
    dis[root] = 0;
    Q.push(root);
    vector<int> p(n, -1), W(m, 1);
    while(!Q.empty()){
        int nd = Q.front(); Q.pop();
        for(auto [x, i]: graph[nd]) if(dis[x] == -1){
            dis[x] = dis[nd]+1;
            p[x] = i;
            W[i] = 0;
            Q.push(x);
        }
    }
 
    vector<int> o(n);
    for(int i = 0; i < n; i++) o[i] = i;
    sort(o.begin(), o.end(), [&](int a, int b){
        return dis[a] > dis[b];
    });
  
    int a = 0, b = n-1;
    while(a < b){
        int md = (a+b)/2;
        vector<int> w = W;
        for(int i = 0; i <= md; i++) if(p[o[i]] != -1) w[p[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);
 
    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 a = 0, b = m-1;
    while(a < b){
        int md = (a+b)/2;
        vector<int> w(m, 0);
        for(int i = 0; i <= md; i++) w[i] = 1;
        ll x = ask(w);
        if(x > def) b = md;
        else a = md+1;
    }
 
    int nd = U[a];
    int s = find_node(nd);
    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: 18 / 18
• Subtask 6: 21 / 31