Submission #70453

#	Time	Username	Problem	Language	Result	Execution time	Memory
70453		MatheusLealV	Teleporters (IOI08_teleporters)	C++17	10 / 100	1079 ms	65868 KiB

teleporters

#include <bits/stdc++.h>
#define N 2000005
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;

int n, m, par[N], ok[N], ans;

vector<int> val;

int bit[N];

void updb(int x, int v)
{
	for(int i = x; i < N; i += (i&-i)) bit[i] += v;
}

int queryb(int x)
{
	int sum = 0;

	for(int i = x; i > 0; i -= (i&-i)) sum += bit[i];

	return sum;
}

int prox(int x)
{
    int ini = 0, fim = val.size() - 1, mid, best;

    while(ini <= fim)
    {
        mid = (ini + fim)/2;

        if(val[mid] > x) best = mid, fim = mid - 1;

        else ini = mid + 1;
    }

    return val[best];
}

int custo = 0;

vector<int> upd;

void dfs(int x, int flag)
{
   // cout<<"DFS "<<x<<"\n";

    if(x == N) return;

    upd.push_back(x);

    int p = prox(x);

    if(!flag)
    {
        if(par[x])
        {
            if(ok[par[x]]) return;

            custo ++;

            dfs(par[x], 1);
        }

        else if(!ok[p]) dfs(p, 0);
    }

    else if(!ok[p]) dfs(p, 0);
}

pii v[N];

int main()
{
    //ios::sync_with_stdio(false); cin.tie(0);

    cin>>n>>m;

    for(int i = 1, x, y; i <= n; i++)
    {
        cin>>x>>y;

        val.push_back(x);

        val.push_back(y);

        par[x] = y, par[y] = x;

        v[i] = {min(x, y), max(x, y)};
    }

     val.push_back(N);

    sort(val.begin(), val.end());

    priority_queue<int> heap;

    custo = 0;

    dfs(0, 0);

    ans = custo;

    for(auto x: upd) ok[x] = 1;

    for(int i = 1; i <= n; i++)
    {
    	int q = upper_bound(val.begin(), val.end(), v[i].s - 1) - lower_bound(val.begin(), val.end(), v[i].f + 1);

    	if(q <= 0)
    	{
    		if(ok[v[i].f] or ok[v[i].s]) heap.push(1);

    		else heap.push(2);
    	}
    }

    for(int i = 1; i < N - 4; i++)
    {
        if(ok[i]) continue;

        upd.clear();

        custo = 0;

       //cout<<"SOLVE "<<i<<"\n";

        dfs(i, 0);
        //if(i == N - 5) cout<<"SOLVE "<<i<<"\n";

        if(custo > 1) heap.push(2*custo);//, cout<<"SECRETO "<<custo<<"\n";

        for(auto x: upd) ok[x] = 1;
    }

    while(!heap.empty() and m > 0)
    {
        m --;

        ans += 2+ heap.top();

        heap.pop();
    }

    ans += 2*m;

    cout<<ans<<"\n";
}

Compilation message (stderr)

teleporters.cpp: In function 'int prox(int)':
teleporters.cpp:41:20: warning: 'best' may be used uninitialized in this function [-Wmaybe-uninitialized]
     return val[best];
                    ^

• Subtask 1: 5 / 5
• Subtask 2: 0 / 5
• Subtask 3: 5 / 5
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• Subtask 20: 0 / 5