제출 #632109

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
632109		arayi	Parking (CEOI22_parking)	C++17	100 / 100	435 ms	87412 KiB

Main

// Arayi
#include <bits/stdc++.h>
#define fr first
#define sc second
#define MP make_pair
#define ad push_back
#define PB push_back
#define fastio                        \
    ios_base::sync_with_stdio(false); \
    cin.tie(0);                       \
    cout.tie(0);
#define lli long long int
#define y1 arayikhalatyan
#define j1 jigglypuff
#define ld long double
#define itn int
#define pir pair<int, int>
#define all(x) (x).begin(), (x).end()
#define str string
#define enl endl
#define en endl
#define cd complex<long double>
#define vcd vector<cd>
#define vii vector<int>
#define vlli vector<lli>
using namespace std;

lli gcd(lli a, lli b) { return (b == 0LL ? a : gcd(b, a % b)); }
ld dist(ld x, ld y1, ld x2, ld y2)
{
    return sqrt((x - x2) * (x - x2) + (y1 - y2) * (y1 - y2));
}
lli S(lli a)
{
    return (a * (a + 1LL)) / 2;
}
mt19937 rnd(363542);
char vow[] = {'a', 'e', 'i', 'o', 'u'};
int dx[] = {0, -1, 0, 1, -1, -1, 1, 1, 0};
int dy[] = {-1, 0, 1, 0, -1, 1, -1, 1, 0};
char dc[] = {'R', 'D', 'L', 'U'};

const int N = 5e5 + 20;
const lli mod = 1e9 + 7;
const ld pi = acos(-1);
const ld e = 1e-13;
const int T = 128;

lli bp(lli a, lli b = mod - 2LL)
{
    lli ret = 1;
    while (b)
    {
        if (b & 1)
            ret *= a, ret %= mod;
        a *= a;
        a %= mod;
        b >>= 1;
    }
    return ret;
}
ostream &operator<<(ostream &c, pir a)
{
    c << a.fr << " " << a.sc;
    return c;
}
template <class T>
void maxi(T &a, T b)
{
    a = max(a, b);
}
template <class T>
void mini(T &a, T b)
{
    a = min(a, b);
}

int n, m;
vii az, ind[N], g[N], g1[N];
bool col[N];
int a[N][2], t[N];
vii tp[3];
vector<pir> pat;
vii gg[N], gg1[N];
priority_queue<pair<int, int>> q;
void dfs(int v, int x1)
{
    if (t[v] == 1)
        gg1[x1].ad(v), gg[v].ad(x1);
    for (auto p : g1[v])
        dfs(p, x1);
}
vii sm;
void dfs1(int v)
{
    bool bl = 0;
    for (auto p : g[v])
    {
        if(!col[p])
        {
            dfs1(p);
            bl = 1;
        }
    }
    if(!bl) sm.ad(v);
}
void han(int i1)
{
    if (col[i1])
        return;
    if (t[i1] == 3)
    {
        if (az.empty())
        {
            cout << -1 << endl;
            exit(0);
        }
        pat.ad(MP(ind[i1][0], az.back()));
        pat.ad(MP(ind[i1][1], az.back()));
        az.pop_back();
        col[i1] = 1;
        for (auto p : gg1[i1])
        {
            for (int i = 0; i < gg[p].size(); i++)
            {
                if (gg[p][i] == i1)
                {
                    swap(gg[p][i], gg[p].back());
                    gg[p].pop_back();
                    break;
                }
            }
            q.push(MP(-gg[p].size(), p));
        }
        for (auto p : g1[i1])
            han(p);
    }
    else if (t[i1] == 2)
    {
        col[i1] = 1;
        pat.ad(MP(ind[i1][1], ind[i1][0]));
        for (auto p : g1[i1])
            han(p);
    }
    else
    {
        if (gg[i1].empty())
        {
            sm.clear();
            dfs1(i1);
            if (sm[0] == i1)
            {
                pat.ad(MP(ind[i1][1], ind[i1][0]));
                az.ad(ind[i1][1]);
                col[i1] = 1;
            }
            else
                for(auto p : sm) han(p);
        }
    }
}

int main()
{
    fastio;
    cin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int a, b;
        cin >> a >> b;
        ::a[i][0] = a, ::a[i][1] = b;
        if (a == 0)
            az.ad(i);
        else
            ind[a].ad(i), ind[b].ad(i);
        if (a == b)
            col[a] = 1;
    }
    for (int i = 1; i <= n; i++)
    {
        if (col[i])
            continue;
        int i1 = ind[i][0], i2 = ind[i][1];
        if (a[i1][0] == i && a[i2][0] == i)
        {
            if (a[i1][1])
                g[i].ad(a[i1][1]);
            if (a[i2][1])
                g[i].ad(a[i2][1]);
            tp[0].ad(i);
            t[i] = 1;
        }
        if (a[i1][1] == i && a[i2][0] == i)
            swap(ind[i][0], ind[i][1]), swap(i1, i2);
        if (a[i1][0] == i && a[i2][1] == i)
        {
            if (a[i1][1])
                g[i].ad(a[i1][1]);
            g1[i].ad(a[i2][0]);
            tp[1].ad(i);
            t[i] = 2;
        }
        if (a[i1][1] == i && a[i2][1] == i)
        {
            g1[i].ad(a[i1][0]);
            g1[i].ad(a[i2][0]);
            tp[2].ad(i);
            t[i] = 3;
        }
        /*cout << i << "-";
        for(auto p : g[i]) cout << p << " ";
        cout << endl;*/
    }
    for (auto p : tp[2])
        dfs(p, p);
    /*for(auto p : tp[0])
    {
        cout << p << "-";
        for(auto p1 : gg[p]) cout << p1 << " ";
        cout << endl;
    }
    for(auto p : tp[2])
    {
        cout << p << "-";
        for(auto p1 : gg1[p]) cout << p1 << " ";
        cout << endl;
    }*/
    for (auto p : tp[0])
        q.push(MP(-gg[p].size(), p));
    while (!q.empty())
    {
        auto p = q.top();
        q.pop();
        if (col[p.sc])
            continue;
        sm.clear();
        dfs1(p.sc);
        for (auto p1 : sm)
            han(p1);
    }
    for (int i = 1; i <= n; i++)
    {
        if (!col[i] && t[i] == 3)
            han(i);
    }
    for (int i = 1; i <= n; i++)
    {
        if (!col[i] && t[i] == 2)
        {
            if (az.empty())
            {
                cout << -1 << endl;
                exit(0);
            }
            pat.ad(MP(ind[i][1], az.back()));
            ind[i][1] = az.back();
            han(g1[i][0]);
        }
    }
    cout << pat.size() << endl;
    for (auto p : pat)
        cout << p.fr << " " << p.sc << "\n";
    return 0;
}

/*
    __
  *(><)*
    \/ /
    ||/
  --||
    ||
    /\
   /  \
  /    \

*/

컴파일 시 표준 에러 (stderr) 메시지

Main.cpp: In function 'void han(int)':
Main.cpp:124:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  124 |             for (int i = 0; i < gg[p].size(); i++)
      |                             ~~^~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 15 / 15
• Subtask 5: 25 / 25
• Subtask 6: 15 / 15