Submission #197917

#	Time	Username	Problem	Language	Result	Execution time	Memory
197917		SamAnd	Teleporters (IOI08_teleporters)	C++17	100 / 100	881 ms	48416 KiB

teleporters

#include <bits/stdc++.h>
using namespace std;
const int N = 2000006;
struct ban
{
    int x, i;
    ban(){}
    ban(int x, int i)
    {
        this->x = x;
        this->i = i;
    }
};
bool operator<(const ban& a, const ban& b)
{
    return a.x < b.x;
}

int u[N];
void mysort(vector<int>& v)
{
    memset(u, 0, sizeof u);
    for (int i = 0; i < v.size(); ++i)
        u[v[i]]++;
    v.clear();
    for (int i = 0; i < N; ++i)
    {
        for (int j = 0; j < u[i]; ++j)
            v.push_back(i);
    }
}

int n, m;
pair<int, int> b[N];

vector<int> v;

int a[N];

bool c[N];
int q;
void dfs(int x)
{
    c[x] = true;
    ++q;
    int h = a[x];
    if (!c[h])
        dfs(h);
}

int main()
{
    #ifdef SOMETHING
    freopen("input.txt", "r", stdin);
    #endif // SOMETHING
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; ++i)
    {
        scanf("%d%d", &b[i].first, &b[i].second);
        v.push_back(b[i].first);
        v.push_back(b[i].second);
    }
    mysort(v);
    for (int i = 1; i <= n; ++i)
    {
        b[i].first = lower_bound(v.begin(), v.end(), b[i].first) - v.begin() + 1;
        b[i].second = lower_bound(v.begin(), v.end(), b[i].second) - v.begin() + 1;
    }
    for (int i = 1; i <= n; ++i)
    {
        a[b[i].first - 1] = (b[i].second);
        a[b[i].second - 1] = (b[i].first);
    }
    int ans = 0;
    q = 0;
    dfs(0);
    ans += (q - 1);
    v.clear();
    for (int i = 1; i <= n * 2; ++i)
    {
        if (!c[i])
        {
            q = 0;
            dfs(i);
            v.push_back(q);
        }
    }
    mysort(v);
    reverse(v.begin(), v.end());
    for (int i = 0; i < min((int)v.size(), m); ++i)
    {
        ans += (v[i] + 2);
    }
    m -= v.size();
    for (int i = 0; i < m; ++i)
    {
        if (i % 2 == 0)
            ans += 1;
        else
            ans += 3;
    }
    printf("%d\n", ans);
    return 0;
}

Compilation message (stderr)

teleporters.cpp: In function 'void mysort(std::vector<int>&)':
teleporters.cpp:23:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < v.size(); ++i)
                     ~~^~~~~~~~~~
teleporters.cpp: In function 'int main()':
teleporters.cpp:56:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
teleporters.cpp:59:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &b[i].first, &b[i].second);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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