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답안 #879568

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
879568 2023-11-27T16:26:49 Z andrei_boaca 통행료 (IOI18_highway) C++17
11 / 100
 800 ms 262144 KB 
#include "highway.h"
#include <bits/stdc++.h>
//#include "grader.cpp"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
mt19937 rng(chrono::steady_clock().now().time_since_epoch().count());
int n,m,niv[100005],par[100005],topar[100005],dp[21][100005],in[100005],out[100005],timp;
ll dist,AA,BB;
vector<pii> muchii[100005];
vector<pii> g;
vector<int> w;
ll memo[100005],calls;
bool isancestor(int a,int b)
{
    return in[a]<=in[b]&&out[a]>=out[b];
}
int LCA(int a,int b)
{
    if(niv[a]>niv[b])
        swap(a,b);
    if(isancestor(a,b))
        return a;
    for(int i=20;i>=0;i--)
        if(dp[i][a]!=-1&&!isancestor(dp[i][a],b))
            a=dp[i][a];
    return par[a];
}
void dfs(int nod)
{
    timp++;
    in[nod]=timp;
    dp[0][nod]=par[nod];
    for(int i=1;i<=20;i++)
    {
        if(dp[i-1][nod]==-1)
        {
            dp[i][nod]=-1;
            continue;
        }
        dp[i][nod]=dp[i-1][dp[i-1][nod]];
    }
    for(auto i:muchii[nod])
        if(i.first!=par[nod])
        {
            par[i.first]=nod;
            niv[i.first]=niv[nod]+1;
            topar[i.first]=i.second;
            dfs(i.first);
        }
    out[nod]=timp;
}
ll buildniv(int p)
{
    if(memo[p]!=0)
        return memo[p];
    for(int i=0;i<m;i++)
    {
        w[i]=1;
        if(min(niv[g[i].first],niv[g[i].second])<=p)
            w[i]=0;
    }
    calls++;
    assert(calls<=60);
    memo[p]=ask(w);
    return memo[p];
}
int getnode(vector<int> cand)
{
    while(true)
    {
        if(cand.size()==1)
            return cand[0];
        vector<int> x,y;
        int lg=cand.size();
        for(int i=0;i<cand.size();i++)
        {
            if(i<lg/2)
                x.push_back(cand[i]);
            else
                y.push_back(cand[i]);
        }
        for(int i=0;i<m;i++)
            w[i]=1;
        for(int i:x)
            w[topar[i]]=0;
        calls++;
        assert(calls<=60);
        ll val=ask(w);
        if(val<dist*BB)
            cand=x;
        else
            cand=y;
    }
    return -1;
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B)
{
    AA=A;
    BB=B;
    n=N;
    m=U.size();
    for(int i=0;i<m;i++)
    {
        int a=U[i],b=V[i];
        g.push_back({a,b});
        muchii[a].push_back({b,i});
        muchii[b].push_back({a,i});
    }
    for(int i=0;i<n;i++)
        par[i]=-1;
    int root=rng()%n;
    niv[root]=1;
    dfs(root);
    int nivmax=0;
    for(int i=0;i<n;i++)
        nivmax=max(nivmax,niv[i]);
    for(int i=0;i<m;i++)
        w.push_back(0);
    calls++;
    assert(calls<=60);
    dist=ask(w)/A;
    int nivlca=nivmax;
    int st=1;
    int dr=nivmax-1;
    while(st<=dr)
    {
        int mij=(st+dr)/2;
        ll val=buildniv(mij);
        if(val<dist*B)
        {
            nivlca=mij;
            dr=mij-1;
        }
        else
            st=mij+1;
    }
    int nivS=nivlca;
    int nivT=0;
    st=nivlca;
    dr=nivmax-1;
    while(st<=dr)
    {
        int mij=(st+dr)/2;
        ll nra=2*(mij-nivlca);
        if(nra<=dist)
        {
            ll val=buildniv(mij);
            ll val2=buildniv(mij-1);
            if(val2==val+2LL*(B-A))
            {
                nivS=mij+1;
                st=mij+1;
                continue;
            }
        }
        dr=mij-1;
    }
    nivT=nivlca+(dist-(nivS-nivlca));
    //assert(nivS<=nivT);
    vector<int> c1,c2;
    for(int i=0;i<n;i++)
    {
        if(niv[i]==nivS)
            c1.push_back(i);
        if(niv[i]==nivT)
            c2.push_back(i);
    }
    int T=getnode(c2);
    if(nivS!=nivT)
    {
        c1.clear();
        for(int i=0;i<n;i++)
            if(niv[i]==nivS&&niv[LCA(i,T)]==nivlca)
                c1.push_back(i);
    }
    int S=getnode(c1);
    //assert(S!=T);
    //assert(S!=-1&&T!=-1);
    answer(S,T);
}

Compilation message

highway.cpp: In function 'int getnode(std::vector<int>)':
highway.cpp:76:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |         for(int i=0;i<cand.size();i++)
      |                     ~^~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 13140 KB Output is correct
2 Correct 2 ms 12632 KB Output is correct
3 Correct 2 ms 12632 KB Output is correct
4 Correct 2 ms 12632 KB Output is correct
5 Correct 2 ms 12632 KB Output is correct
6 Correct 2 ms 12632 KB Output is correct
7 Correct 2 ms 12632 KB Output is correct
8 Correct 2 ms 12632 KB Output is correct
9 Correct 2 ms 12632 KB Output is correct
10 Correct 2 ms 12632 KB Output is correct
11 Correct 2 ms 12632 KB Output is correct
12 Correct 2 ms 12632 KB Output is correct

Subtask #2
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 12732 KB Output is correct
2 Correct 10 ms 13652 KB Output is correct
3 Incorrect 89 ms 20288 KB Output is incorrect: {s, t} is wrong.
4 Halted 0 ms 0 KB -

Subtask #3
6.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 10 ms 14036 KB Output is correct
2 Correct 21 ms 15480 KB Output is correct
3 Correct 24 ms 16632 KB Output is correct
4 Correct 79 ms 23796 KB Output is correct
5 Correct 70 ms 23712 KB Output is correct
6 Correct 78 ms 23032 KB Output is correct
7 Correct 71 ms 24584 KB Output is correct
8 Correct 81 ms 24096 KB Output is correct
9 Correct 73 ms 24532 KB Output is correct

Subtask #4
0 / 33.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 12632 KB Output is correct
2 Correct 9 ms 13580 KB Output is correct
3 Incorrect 75 ms 18876 KB Output is incorrect: {s, t} is wrong.
4 Halted 0 ms 0 KB -

Subtask #5
0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 800 ms 262144 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -

Subtask #6
0 / 31.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 520 ms 262144 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -