Submission #583303

#	Time	Username	Problem	Language	Result	Execution time	Memory
583303		hibiki	Teleporters (IOI08_teleporters)	C++11	100 / 100	418 ms	23580 KiB

teleporters

#include<bits/stdc++.h>
using namespace std;

#define pb push_back
#define f first
#define s second
#define all(x) x.begin(),x.end()

int n,m;
pair<int,int> go[2000005];
bool pass[2000005];

int main()
{
    scanf("%d %d",&n,&m);
    for(int i = 0; i < 2000005; i++)
        go[i] = {i + 1, 0};
    for(int i = 0; i < n; i++)
    {
        int a,b;
        scanf("%d %d",&a,&b);
        go[a] = {b + 1, 1};
        go[b] = {a + 1, 1};
    }

    int ans = 0;
    priority_queue<int> pq;
    pass[2000005 - 1] = true;
    for(int i = 0; i < 2000005; i++)
    {
        if(pass[i]) continue;

        int cnt = 0, nw = i;
        while(!pass[nw])
        {
            pass[nw] = true;
            cnt += go[nw].s;
            nw = go[nw].f;
        }

        if(i == 0)
            ans += cnt;
        else
        {
            // printf("%d %d\n",i,cnt);
            pq.push(cnt);
        }
    }

    while(m > 0 && !pq.empty())
    {
        ans += pq.top() + 2;
        pq.pop();
        m--;
    }
    ans += (m / 2) * 4 + (m % 2);
    printf("%d\n",ans);
    return 0;
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:15:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     scanf("%d %d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~~
teleporters.cpp:21:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         scanf("%d %d",&a,&b);
      |         ~~~~~^~~~~~~~~~~~~~~

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