Submission #1211035

#	Time	Username	Problem	Language	Result	Execution time	Memory
1211035		garam1732	Highway Tolls (IOI18_highway)	C++20	In queue	0 ms	0 KiB

highway

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

#define ff first
#define ss second
#define bl ' '
#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define comp(v) (v).erase(unique(all(v)), (v).end())
#define lbd(v,x) lower_bound(all(v), (x))-(v).begin()
#define ubd(v,x) upper_bound(all(v), (x))-(v).begin()

typedef long long ll;
typedef pair<int, int> pi;
typedef pair<pi, int> pii;
typedef pair<int, pi> ipi;
typedef pair<pi, pi> pipi;
typedef pair<ll, ll> pll;

const int MAXN = 100100*1;
const ll MOD = 998244353;
const ll INF = 1e16;

vector<int> adj[MAXN];
bool chk[MAXN];

queue<pi> q;
vector<ll> d;
vector<int> v[2];
void bfs(int s, int t) {
    d[s] = d[t] = 0; q.push(pi(s, 0)); q.push(pi(t, 1));
    while(q.size()) {
        int here = q.front().ff; int col = q.front().ss; q.pop();
        v[col].push_back(here);

        for(int there : adj[here]) {
            if(d[there] > d[here]+1) {
                d[there] = d[here]+1;
                q.push(pi(there, col));
            }
        }
    }
}

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

    vector<int> w(m);
    ll len = ask(w)/A;
    int lb = 0, ub = m-1, mid;
    while(lb < ub) {
        mid = lb+ub>>1;
        for(int i=lb; i<=mid; i++) w[i]=1;
        ll res = ask(w);

        if(res > A*len) {
            for(int i=lb; i<=mid; i++) w[i]=0;
            ub = mid;
        } else {
            lb = mid+1;
        }
    } int e = lb;

    int x = U[e], y = V[e];
    d.resize(N, INF); bfs(x, y);

    int ans[2];
    for(int t : {0,1}) {
        lb = 0, ub = (int)v[t].size()-1, mid;
        while(lb < ub) {
            mid = lb+ub>>1;

            w.clear(); w.resize(m);
            memset(chk, 0, sizeof chk);
            for(int i=mid+1; i<v[t].size(); i++) chk[v[t][i]] = 1;
            for(int i=0; i<m; i++) {
                if(chk[U[i]] != chk[V[i]]) w[i] = 1;
            } ll res = ask(w);

            if(res == A*len) ub = mid;
            else lb = mid+1;
        } ans[t] = v[t][lb];
    }

	answer(ans[0], ans[1]);
}