Submission #140324

#	Time	Username	Problem	Language	Result	Execution time	Memory
140324		XmtosX	Highway Tolls (IOI18_highway)	C++17	5 / 100	1561 ms	262144 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
const int MAXN=90005;
int n,m,par[MAXN];
vector <int> v[MAXN];
vector <pair<int,int> > vv;
map <pair<int,int>, int> r;
long long ANS;
void dfs (int x,int p,int l)
{
    vv.push_back({l,x});
    par[x]=p;
    for (int i=0;i<v[x].size();i++)
    {
        if (v[x][i]!=p)
        {
            dfs(v[x][i],x,l+1);
        }
    }
}
void find_pair (int N, vector<int> U, vector<int> V, int A, int B)
{
    n=N;
    m=U.size();
    vector<int> w;
    w.resize(m);
    ANS=ask(w);
    for (int i=0;i<m;i++)
    {
        v[U[i]].push_back(V[i]);
        v[V[i]].push_back(U[i]);
        r[{U[i],V[i]}]=i;
        r[{V[i],U[i]}]=i;
    }
    dfs(0,-1,1);
    int low=0,high=vv.size(),mid,ans=-1;
    while (low<=high)
    {
        for (int i=0;i<w.size();i++)
            w[i]=0;
        mid=(low+high)/2;
        for (int i=mid;i<vv.size();i++)
        {
            int a=vv[i].second;
            w[r[{a,par[a]}]]=1;
        }
        if (ask(w)!=ANS)
        {
            ans=vv[mid].second;
            low=mid+1;
        }
        else
            high=mid-1;
    }
    answer(0,ans);
}

Compilation message (stderr)

highway.cpp: In function 'void dfs(int, int, int)':
highway.cpp:14:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0;i<v[x].size();i++)
                  ~^~~~~~~~~~~~
highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:40:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=0;i<w.size();i++)
                      ~^~~~~~~~~
highway.cpp:43:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=mid;i<vv.size();i++)
                        ~^~~~~~~~~~

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