Submission #290127

#	Time	Username	Problem	Language	Result	Execution time	Memory
290127		dandrozavr	Highway Tolls (IOI18_highway)	C++14	0 / 100	22 ms	11384 KiB

highway

#include "highway.h"
#include <vector>
#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>

#define TIME 1.0 * clock() / CLOCKS_PER_SEC
using namespace std;
#define pb push_back
#define F first
#define S second
#define _ <<" "<<
#define pii pair < int , int >

const int N = 2e5 + 5;
vector < pii > g[N];
vector < int > emp;
int Len, a, b;

void dfs(int v, int pr, int len){
//    cout << v _ pr _ len << endl;
    if (!len){
        answer(0, v);
        return;
    }
    vector < pii > vis;
    for (pii to : g[v])
        if (to.F != pr) vis.pb(to);
//    for (auto i : vis) cout << i.F _ i.S << endl;
//    cout<<endl;
    if (vis.size() == 1){
        dfs(vis[0].F, v, len - 1);
        return;
    }
    int l = 0, r = vis.size() - 1;
    while(l < r){
        int mid = (l + r) >> 1;
        for (int i = 0; i <= mid; ++i) emp[vis[i].S] = 1;
//        cout << mid _ ask(emp) << endl;
        if (ask(emp) == Len * a) l = mid + 1; else r = mid;
        for (int i = 0; i < mid; ++i) emp[vis[i].S] = 0;
    }
//    cout<<endl;
    dfs(vis[l].F, v, len - 1);
}

void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
    a = A;
    b = B;
    int n = N;
    int m = U.size();
    for (int i = 0; i < m; ++i){
        int x = U[i];
        int y = V[i];
        g[x].pb({y, i});
        g[y].pb({x, i});
    }
    vector < int > vc(m, 0);
    emp = vc;
    Len = ask(vc) / A;
    if (Len == 0){
        answer(0, 0);
        return;
    }
    dfs(0, -1, Len);
//    cout<<"BAD\n";
}

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:50:9: warning: unused variable 'n' [-Wunused-variable]
   50 |     int n = N;
      |         ^

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