oj.uz

Submission #877029

# Submission time Handle Problem Language Result Execution time Memory
877029 2023-11-22T18:31:14 Z andrei_iorgulescu Stranded Far From Home (BOI22_island) C++14
0 / 100
 759 ms 154552 KB 
#include <bits/stdc++.h>

using namespace std;

#define int long long

struct cmp2
{
    bool operator() (pair<int,int>x,pair<int,int>y) const
    {
        if (x.first != y.first)
            return x.first < y.first;
        return false;
    }
};

struct grup
{
    vector<int>noduri_alive;
    int nr_oameni;
    multiset<pair<int,int>,cmp2>edges;
};

int n,m,s[200005];
vector<pair<int,int>>G[200005];
int t[200005],sz[200005];
grup g[200005];
bool sol_finala[200005];

bool cmp(int x,int y)
{
    if (g[x].nr_oameni != g[y].nr_oameni)
        return g[x].nr_oameni < g[y].nr_oameni;
    return x < y;
}

multiset<int,decltype(cmp)*>st(cmp);

int ancestor(int nod)
{
    while (nod != t[nod])
        nod = t[nod];
    return nod;
}

void join(int x,int y)
{
    if (sz[x] < sz[y])
        swap(x,y);
    sz[x] += sz[y];
    t[y] = x;
    g[x].nr_oameni += g[y].nr_oameni;
    for (auto it : g[y].noduri_alive)
        g[x].noduri_alive.push_back(it);
    for (auto it : g[y].edges)
        g[x].edges.insert(it);
    g[y].nr_oameni = 0;
    g[y].noduri_alive.clear();
    g[y].edges.clear();
    st.insert(x);
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        cin >> s[i];
    for (int i = 1; i <= m; i++)
    {
        int x,y;
        cin >> x >> y;
        G[x].push_back({s[y],y});
        G[y].push_back({s[x],x});
    }
    for (int i = 1; i <= n; i++)
    {
        t[i] = i;
        sz[i] = 1;
        g[i].noduri_alive = {i};
        g[i].nr_oameni = s[i];
        for (auto it : G[i])
            g[i].edges.insert(it);
        st.insert(i);
    }
    while (st.size() >= 2)
    {
        /*for (auto it : st)
        {
            cout << it << ' ' << g[it].nr_oameni << endl;
            for (auto itt : g[it].noduri_alive)
                cout << itt << ' ';
            cout << endl;
            for (auto itt : g[it].edges)
                cout << itt.first << ' ' << itt.second << endl;
            cout << endl;
        }
        cout << endl;*/
        int nod = *st.begin();
        //cout << nod << endl;
        while (true)
        {
            pair<int,int>aux = *(g[nod].edges.begin());
            if (ancestor(aux.second) == nod)
                g[nod].edges.erase(aux);
            else
                break;
        }
        pair<int,int>aux = *(g[nod].edges.begin());
        //cout << aux.first << ' ' << aux.second << endl;
        g[nod].edges.erase(g[nod].edges.begin());
        if (aux.first > g[nod].nr_oameni)
        {
            //cout << "caz1 " << nod << endl;
            st.erase(nod);
            g[nod].noduri_alive.clear();
        }
        else
        {
            //cout << "caz2 " << nod << ' ';
            int x = aux.second;
            x = ancestor(x);
            //cout << x << endl;
            st.erase(st.find(nod));
            //cout << st.size() << endl;
            if (g[x].noduri_alive.size() != 0)
                st.erase(x);
            join(nod,x);
        }
    }
    for (auto it : st)
    {
        for (auto x : g[it].noduri_alive)
            sol_finala[x] = true;
    }
    for (int i = 1; i <= n; i++)
    {
        if (sol_finala[i] == false)
            cout << 0;
        else
            cout << 1;
    }
    return 0;
}

/**
fiecare muchie devine defapt doua muchii, una x -> y cu cost s[y] si una y -> x cu cost s[x]

iau grupul cu macar un nod alive cu cei mai putini oameni si muchia lui spre un nod cu s cat mai mic
daca nu le pot conecta, marchez ca not alive toate nodurile alive din grup
daca le pot conecta, fac un small to large pe noduri (nu conteaza daca alive sau nu) pentru a le uni

ok, idee penala, acum ramane cum implementez

tin un dsu pentru grupuri, iar in tatal grupului tin:
-nodurile alive din grup
-cate alive am
-cati oameni am
-muchiile, sortate dupa cost

imi pot tine un set cu tatii grupurilor cu macar un nod alive, pentru fiecare retinand:
-ofc nodul tata
-numarul de oameni

o sa am ceva gen:

while (setul mai are >= 2 grupuri alive)
{
    iau si eu grupul din set cu numar minim de oameni
    lui ii iau muchia minima pentru care nu sunt ambele noduri conectate de muchie in grupul lui nod
    daca pe muchia asta nu pot conecta, atunci scot din set nodul nod (si atat)
    daca pe muchia asta pot conecta, am doua cazuri:
    1. nodul de care conectez nu e alive -> il scot pe asta din set, le dau join si bag combinata lor in set
    2. nodul de care conectez e alive -> ii scot pe ambii din set, le dau join si bag combinata lor in set
}

apoi, din grupul care mi-a mai ramas singur in set, afisez alea alive
**/

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 24924 KB Output is correct
2 Correct 5 ms 24924 KB Output is correct
3 Correct 5 ms 24924 KB Output is correct
4 Runtime error 24 ms 51404 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 24920 KB Output is correct
2 Correct 5 ms 25028 KB Output is correct
3 Correct 643 ms 85440 KB Output is correct
4 Runtime error 341 ms 154552 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 24920 KB Output is correct
2 Runtime error 759 ms 153360 KB Execution killed with signal 11
3 Halted 0 ms 0 KB -

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 24920 KB Output is correct
2 Runtime error 270 ms 154320 KB Execution killed with signal 11
3 Halted 0 ms 0 KB -

Subtask #5
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 24924 KB Output is correct
2 Correct 5 ms 24924 KB Output is correct
3 Correct 5 ms 24924 KB Output is correct
4 Runtime error 24 ms 51404 KB Execution killed with signal 11
5 Halted 0 ms 0 KB -