Submission #113704

#	Time	Username	Problem	Language	Result	Execution time	Memory
113704		zoooma13	Highway Tolls (IOI18_highway)	C++14	51 / 100	326 ms	13780 KiB

highway

#include "highway.h"
#include "bits/stdc++.h"
using namespace std;

#define MAX_N 90004

//#include "grader.cpp"

int n ,m;
vector <pair <int ,int>> adj[MAX_N];

int par[MAX_N];
vector <pair<int ,int>> nodes;
void bfs(int s){
    nodes.clear();

    queue <pair<int,int>> nxt;
    nxt.push({s ,par[s]});

    while(!nxt.empty()){
        int u = nxt.front().first ,f = nxt.front().second; nxt.pop();
          //  cout << u << endl;
        nodes.push_back({u ,f});
        for(auto e : adj[u])
            nxt.push(e);
    }
}
/**
4 4 1 3 1 3
0 1
0 2
0 3
1 2
*/
int solve(int u ,long long dist){
    bfs(u);
    int st = 0 ,en = nodes.size()-1 ,mid;
    while(st < en){
        mid = (st+en+1)>>1;
        vector <int> w(m ,0);
        for(int i=mid; i<=en; i++)
            w[nodes[i].second] = 1;
        if(ask(w) != dist)
            st = mid;
        else
            en = mid-1;
    }
    return nodes[st].first;
}

vector <pair<int ,int>> t_adj[MAX_N];
void get_bfs_tree(int s){
    vector <bool> vis(n); vis[s] = 1;
    queue <int> nxt; nxt.push(s);
    while(!nxt.empty()){
        int u = nxt.front(); nxt.pop();
        for(auto e : adj[u])
            if(!vis[e.first]){
                vis[e.first] = 1;
                nxt.push(e.first);

                t_adj[u].push_back(e);
                par[e.first] = e.second;
            }
    }
    for(int i=0; i<n; i++)
        swap(adj[i] ,t_adj[i]);
}

void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
    n = N ,m = U.size();
    for(int i=0; i<m; i++)
        adj[U[i]].push_back({V[i] ,i}),
        adj[V[i]].push_back({U[i] ,i});

    long long dist = ask(vector<int>(m ,0));
    int st = 0 ,en = m ,mid;
    while(st < en){
        mid = (st+en)>>1;
        vector <int> w(m ,0);
        for(int i=st; i<=mid; i++)
            w[i] = 1;
        if(ask(w) != dist)
            en = mid;
        else
            st = mid+1;
    }

    get_bfs_tree(U[en]);
    par[U[en]] = en;
    adj[U[en]].erase(find(adj[U[en]].begin() ,adj[U[en]].end() ,make_pair(V[en] ,en)));

    int s = solve(U[en] ,dist);
    int t = solve(V[en] ,dist);
    //cout << s << ' ' << t << endl;
    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