Submission #797800

#	Time	Username	Problem	Language	Result	Execution time	Memory
797800		TB_	Stranded Far From Home (BOI22_island)	C++17	20 / 100	1077 ms	41032 KiB

island

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

// #undef _GLIBCXX_DEBUG                // disable run-time bound checking, etc
// #pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
// #pragma GCC optimize ("unroll-loops")

// #pragma GCC target("bmi,bmi2,lzcnt,popcnt")                      // bit manipulation
// #pragma GCC target("movbe")                                      // byte swap
// #pragma GCC target("aes,pclmul,rdrnd")                           // encryption
// #pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2") // SIMD

// #include <bits/extc++.h>
// using namespace __gnu_pbds;
// template<class T>using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
// template<class T>using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long
#define INF (ll)1e9+7
#define fo(i, n) for(int i=0;i<((ll)n);i++)
#define deb(x) cout << #x << " = " << x << endl;
#define deb2(x, y) cout << #x << " = " << x << ", " << #y << " = " << y << endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define LSOne(S) ((S) & (-S))
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
inline int readint(){ int v = 0; char c; while((c = getchar()) != EOF && c != ' ' && c != '\n'){ v *= 10; v += c - '0'; } return v; }
inline int readintsigned() { int v = 0; int sign = 1; char c = getchar(); if (c == '-') { sign = -1; } else { v += c - '0'; } while ((c = getchar()) != EOF && c != ' ' && c != '\n') { v *= 10; v += c - '0'; } return v * sign; }
inline string readstring() { string s; char c; while ((c = getchar()) != EOF && c != '\n' && c != ' ') { s.push_back(c); } return s; }
template <class result_t=std::chrono::milliseconds,class clock_t=std::chrono::steady_clock,class duration_t = std::chrono::milliseconds>
auto since(std::chrono::time_point<clock_t, duration_t> const& start){return std::chrono::duration_cast<result_t>(clock_t::now() - start);}
typedef pair<int, int> pii;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpii;
typedef vector<pl> vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vpii> vvpii;
typedef vector<vpl> vvpl;

ll n, m, val, from, to, w;
vl population;

vvl adj(200001);

struct UnionFind{
    int n;
    vl p, siz;
    UnionFind(int n) : n(n){
        p.assign(n, -1);
        siz.assign(n, 1);
        fo(i, n)p[i] = i;
    }

    int find(int x){
        if(p[x] == x) return x;
        return p[x] = find(p[x]);
    }

    void unite(int a, int b){
        a = find(a);
        b = find(b);
        if(a == b) return;
        if(siz[b] > siz[a]) swap(a, b);
        siz[a]+=siz[b];
        p[b] = a;
    }
};

int main() {
    // cout << fixed << setprecision(20);
    // auto start = std::chrono::steady_clock::now(); // since(start).count()
    cin.tie(0)->sync_with_stdio(0);
    mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

    cin >> n >> m;
    pii biggestPop = {-1, -1};
    vpl popSort;
    fo(i, n){
        cin >> val;
        population.pb(val);
        biggestPop = max(biggestPop, {val, i});
        popSort.pb({val, i});
    }

    sort(all(popSort));

    fo(i, m){
        cin >> from >> to;
        adj[--from].pb(--to);
        adj[to].pb(from);
    }
    vi ans(n, -1);
    ans[biggestPop.S] = 1;

    vi order;
    fo(i, n) order.pb(popSort[i].S);
    // shuffle(all(order), rng);

    UnionFind uf(n);

    vi seen(n, 0);
    for(auto start : order){
        start = uf.find(start);
        if(ans[start] != -1) continue;
        vi visited;
        set<pl> s = {{0, start}};

        ll currentPop = population[start];
        while(!s.empty()){
            auto res = s.lower_bound({currentPop, INF});
            if(res == s.begin()) {
                if(seen[uf.find((*res).S)]) continue;
                for(int i = 1; i < visited.size(); i++){
                    uf.unite(visited[0], visited[i]);
                    for(auto v : adj[visited[i]]){
                        if(seen[v]) continue;
                        seen[v] = 1;
                        adj[visited[0]].pb(v);
                    }
                }
                population[visited[0]] = currentPop;
                for(auto v : adj[visited[0]]) seen[v] = 0;
                visited = {visited[0]};
                seen[visited[0]] = 1;
                ans[visited[0]] = 0;
                start = uf.find((*res).S);
                res++;
            }


            tie(w, to) = *--res;
            to = uf.find(to);
            s.erase(res);
            if(seen[to]) continue;
            seen[to] = 1;
            visited.pb(to);
            currentPop += w;
            if(ans[to] == 1 || currentPop >= biggestPop.F) break;
            for(auto v : adj[to]){
                v = uf.find(v);
                s.insert({population[v], v});           
            }
        }
        ans[start] = 1;
        for(auto v : visited) 
            seen[uf.find(v)] = 0;
        
    }
    fo(i, n) cout << ans[uf.find(i)];

    return 0;
}

Compilation message (stderr)

island.cpp: In function 'int main()':
island.cpp:119:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  119 |                 for(int i = 1; i < visited.size(); i++){
      |                                ~~^~~~~~~~~~~~~~~~

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