Submission #654476

#	Time	Username	Problem	Language	Result	Execution time	Memory
654476		prvocislo	Stranded Far From Home (BOI22_island)	C++17	25 / 100	1025 ms	29232 KiB

island

#include <algorithm>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <string>
#include <vector>
typedef long long ll;
typedef long double ld;
using namespace std;

const int maxn = 2e5 + 5;
struct comp
{
    ll sum = 0;
    vector<int> s;
};
vector<comp> c(maxn);
vector<int> a(maxn), p(maxn);
int root(int u)
{
    return u == p[u] ? u : p[u] = root(p[u]);
}
int merge(int u, int v)
{
    u = root(u), v = root(v);
    if (u == v) return u;
    if (c[u].s.size() < c[v].s.size()) swap(u, v);
    p[v] = u;
    c[u].sum += c[v].sum;
    vector<int> un;
    int iu = 0, iv = 0;
    while (un.size() < c[u].s.size() + c[v].s.size())
    {
        if (iu < c[u].s.size() && (iv == c[v].s.size() || a[c[u].s[iu]] < a[c[v].s[iv]])) un.push_back(c[u].s[iu++]);
        else un.push_back(c[v].s[iv++]);
    }
    c[u].s = un;
    return u;
}
bool cmp(int i, int j)
{
    return a[i] < a[j];
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, m;
    cin >> n >> m;
    vector<pair<int, int> > w;
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
        w.push_back({ a[i], i });
        c[i].sum = a[i];
        p[i] = i;
    }
    vector<vector<int> > g(n);
    for (int i = 0; i < m; i++)
    {
        int u, v;
        cin >> u >> v;
        u--, v--;
        if (make_pair( a[u], u ) > make_pair( a[v], v )) swap(u, v);
        c[u].s.push_back(v);
        g[v].push_back(u);
    }
    for (int i = 0; i < n; i++) sort(c[i].s.begin(), c[i].s.end(), cmp);
    vector<int> de(n, -1);
    sort(w.begin(), w.end());
    for (pair<int, int> p : w)
    {
        int u = p.second, cm = u;
        for (int v : g[u]) cm = merge(cm, v);
        vector<int> bad = c[cm].s;
        c[cm].s.clear();
        for (int i : bad) if (i != u) c[cm].s.push_back(i);
        if (!c[cm].s.empty() && a[c[cm].s[0]] <= c[cm].sum) de[u] = c[cm].s[0];
    }
    reverse(w.begin(), w.end());
    vector<bool> ans(n, false);
    for (pair<int, int> p : w)
    {
        int u = p.second;
        if (p == w[0]) ans[u] = true;
        else if (de[u] != -1) ans[u] = ans[de[u]];
    }
    for (int i = 0; i < n; i++) cout << "01"[ans[i]];
    cout << "\n";
    return 0;
}

Compilation message (stderr)

island.cpp: In function 'int merge(int, int)':
island.cpp:42:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         if (iu < c[u].s.size() && (iv == c[v].s.size() || a[c[u].s[iu]] < a[c[v].s[iv]])) un.push_back(c[u].s[iu++]);
      |             ~~~^~~~~~~~~~~~~~~
island.cpp:42:39: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         if (iu < c[u].s.size() && (iv == c[v].s.size() || a[c[u].s[iu]] < a[c[v].s[iv]])) un.push_back(c[u].s[iu++]);
      |                                    ~~~^~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 15 / 15
• Subtask 4: 0 / 30
• Subtask 5: 0 / 35