Submission #293463

#	Time	Username	Problem	Language	Result	Execution time	Memory
293463		Trickster	통행료 (IOI18_highway)	C++14	12 / 100	214 ms	76640 KiB

highway

#include <algorithm>
#include <highway.h>
#include <string.h>
#include <iostream>
#include <stdio.h>
#include <vector>
#include <queue>
#include <cmath>
#include <set>
#include <map>

using namespace std;

#define maxN 200010
#define ff first
#define ss second
#define ll long long
#define pb push_back
#define mod 1000000007
#define pii pair <ll, ll>
// #pragma GCC target ("avx2")
// #pragma GCC optimization ("O3")
// #pragma GCC optimization ("unroll-loops")
ll bigmod(ll a,ll e) {if(e==0)return 1;ll x=bigmod(a*a%mod,e>>1);return e&1?x*a%mod:x;}

int n, m;
int D[maxN];
int L[maxN];
vector <int> Lin, node;
vector <pii> Lv[maxN], E[maxN];

void dfs(int nd, int pr, int in)
{
    node.pb(nd);
    if(in != -1) {
        Lin.pb(in);
        L[nd] = L[pr]+1;
        Lv[L[nd]].pb({nd, in});
    }

    for(auto i: E[nd]) {
        if(i.ff == pr) continue;

        dfs(i.ff, nd, i.ss);
    }
}

void find_pair(int N, vector <int> U, vector <int> V, int A, int B) 
{
    m = U.size(), n = N;

    for(int i = 0; i < m; i++) {
        E[U[i]].pb({V[i], i});
        E[V[i]].pb({U[i], i});

        D[U[i]]++;
        D[V[i]]++;
    }

    int ok = 1, x = 0;
    for(int i = 0; i < n; i++) {
        if(D[i] > 2) ok = 0;
        if(D[i] == 1) x = i;
    }

    vector <int> arr;
    for(int i = 0; i < m; i++) arr.pb(0);

    int ans = ask(arr) / A;

    if(ok == 0) {
        dfs(0, -1, -1);

        int l = 0, r = Lv[ans].size()-1, md, S = 0, T;
        while(l <= r) {
            md = (l+r)/2;
    
            vector <int> arr;
            for(int h = 0; h < m; h++) arr.pb(0);
    
            for(int i = 0; i <= md; i++) arr[Lv[ans][i].ss] = 1;
    
            int cur = ask(arr);
    
            if(ans * A != cur) r = md-1, T = md;
            else l = md+1;
        }
    
        answer(S, Lv[ans][T].ff);
    }
    else {
        dfs(x, -1, -1);

        int l = 0, r = m-1, md, in = 0;
        while(l <= r) {
            md = (l+r)/2;

            vector <int> arr;
            for(int i = 0; i < m; i++) arr.pb(0);

            for(int i = 0; i <= md; i++) arr[Lin[i]] = 1;

            int cur = ask(arr);

            if(ans * A != cur) r = md-1, in = md;
            else l = md+1;
        }

        answer(node[in], U[ans+in]);
    }
}

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:89:28: warning: 'T' may be used uninitialized in this function [-Wmaybe-uninitialized]
   89 |         answer(S, Lv[ans][T].ff);
      |                            ^

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