제출 #754766

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
754766		GrindMachine	통행료 (IOI18_highway)	C++17	51 / 100	159 ms	9296 KiB

highway

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
edi

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

#include "highway.h"

void find_pair(int n, std::vector<int> U, std::vector<int> V, int A, int B) {
    int m = sz(U);
    assert(m == n-1);

    vector<pii> adj[n];

    rep(i,n-1){
        int u = U[i], v = V[i];
        adj[u].pb({v,i}), adj[v].pb({u,i});
    }

    auto solve_for_one_special_guy_in_component = [&](int root, int break_edge){
        vector<pii> order;
        queue<int> q;
        vector<bool> vis(n);
        q.push(root);
        vis[root] = 1;

        order.pb({root,-1});
    
        while(!q.empty()){
            int u = q.front();
            q.pop();

            for(auto [v,id] : adj[u]){
                if(vis[v]) conts;
                if(id == break_edge) conts;
                q.push(v);
                vis[v] = 1;
                order.pb({v,id});
            }
        }

        int l = 0, r = sz(order)-1;
        int ans = -1;

        ll original = 0;

        {
            vector<int> all_zero(n-1);
            original = ask(all_zero);
        }

        while(l <= r){
            // does t lie in order[0..mid]?
            int mid = (l+r) >> 1;
            vector<int> a(n-1);
            for(int i = mid + 1; i < sz(order); ++i){
                int id = order[i].ss;
                a[id] = 1;    
            }

            ll res = ask(a);

            if(res == original){
                ans = order[mid].ff;
                r = mid - 1;
            }
            else{
                l = mid + 1;
            }
        }

        return ans;
    };

    ll original = 0;

    {
        vector<int> all_zero(n-1);
        original = ask(all_zero);
    }

    int l = 0, r = n-1;
    int first = -1;

    while(l <= r){
        int mid = (l+r) >> 1;
        vector<int> a(n-1);
        rep(i,mid+1) a[i] = 1;
        ll res = ask(a);

        if(res != original){
            first = mid;
            r = mid - 1;
        }
        else{
            l = mid + 1;
        }
    }

    assert(first != -1);

    int r1 = U[first], r2 = V[first];

    int s = solve_for_one_special_guy_in_component(r1,first);
    int t = solve_for_one_special_guy_in_component(r2,first);

    answer(s,t);
}

컴파일 시 표준 에러 (stderr) 메시지

highway.cpp: In lambda function:
highway.cpp:112:36: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  112 |             for(int i = mid + 1; i < sz(order); ++i){
      |                                    ^

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