Submission #997599

#	Time	Username	Problem	Language	Result	Execution time	Memory
997599		underwaterkillerwhale	Stranded Far From Home (BOI22_island)	C++17	10 / 100	643 ms	189280 KiB

island

#include <bits/stdc++.h>
#define se              second
#define fs              first
#define mp              make_pair
#define pb              push_back
#define ll              long long
#define ii              pair<ll,ll>
#define ld              long double
#define SZ(v)           (int)v.size()
#define ALL(v)          v.begin(), v.end()
#define bit(msk, i)     ((msk >> i) & 1)
#define iter(id, v)     for(auto id : v)
#define rep(i,m,n)      for(int i=(m); i<=(n); i++)
#define reb(i,m,n)      for(int i=(m); i>=(n); i--)

using namespace std;

mt19937_64 rd(chrono :: steady_clock :: now().time_since_epoch().count());
ll Rand(ll l, ll r) { return uniform_int_distribution<ll> (l, r)(rd); }

const int N  = 5e5 + 7;
const int Mod = 998244353;
const int szBL = 916;
const int INF = 1e9;
const int BASE = 137;

int n, m;
vector<int> ke[N];
int a[N];

bool Ans[N];
int larger[N];

pair<int,int> b[N];

struct Disjoin_set {
    int lab[N], sz[N];
    ll tot[N];
    vector<int> vec[N];
    set<pair<int,int>> Sadj[N];///greater val

    void init (int n) {
        rep (i, 1, n) {
            lab[i] = i, sz[i] = 1, tot[i] = a[i];
            vec[i] = {i};
            iter (&id, ke[i]) {
                Sadj[i].insert(mp(a[id], id));
            }
        }
    }

    int Find (int u) {
        return u == lab[u] ? u : lab[u] = Find(lab[u]);
    }

    void Join (int u, int v) { /// u wanna combine, not v
        if (a[u] < a[v]) return;
        u = Find(u);
        v = Find(v);
        if (u == v) return;
        if (sz[u] < sz[v]) swap(u, v);
        lab[v] = u;
        sz[u] += sz[v];
        iter (&id, vec[v]) {
            iter (&idto, ke[id]) {
                Sadj[u].insert(mp(a[idto], idto));
            }
            vec[u].push_back(id);
        }
        tot[u] += tot[v];
        vector<int> ().swap(vec[v]);
    }
    int Find_Larger (int u) {
        int idx = u;
        u = Find(u);
        auto it = Sadj[u].lower_bound(mp(a[idx] + 1, -INF));
//        cout << idx <<": "; iter (&id, Sadj[u]) cout << id.se <<" ";
//        cout<<"\n";
        if (it == Sadj[u].end()) return -1;
        else return it->se;
    }
}DSU;

struct Disjoin_set2 {
    int lab[N], sz[N];
    ll tot[N];
    struct Data {
        int labu, labv, szu, szv;
        ll totu, totv;
    };
    stack<Data> op;
    void init (int n) {
        rep (i, 1, n) {
            lab[i] = i, sz[i] = 1, tot[i] = a[i];
        }
    }

    int Find (int u) {
        return u == lab[u] ? u : lab[u] = Find(lab[u]);
    }

    void Join (int u, int v) { /// u wanna combine, not v
        u = Find(u);
        v = Find(v);
        op.push({lab[u], lab[v], sz[u], sz[v], tot[u], tot[v]});
        if (u == v) return;
        if (sz[u] < sz[v]) swap(u, v);
        lab[v] = u;
        sz[u] += sz[v];
        tot[u] += tot[v];
    }
    void roll_back() {
        Data cur = op.top();
        op.pop();
        int u = cur.labu, v = cur.labv;
        lab[u] = cur.labu;
        lab[v] = cur.labv;
        sz[u] = cur.szu;
        sz[v] = cur.szv;
        tot[u] = cur.totu;
        tot[v] = cur.totv;
    }

}DSU2;

void solution () {
    cin >> n >> m;
    rep (i, 1, n) {
        cin >> a[i];
        b[i].fs = a[i];
        b[i].se = i;
    }
    rep (i, 1, m) {
        int u, v;
        cin >> u >> v;
        ke[u].push_back(v);
        ke[v].push_back(u);
    }
    DSU.init(n);
    DSU2.init(n);
    sort (b + 1, b + 1 + n);
    rep (i, 1, n) {
        int idx = b[i].se;
        iter (&to, ke[idx]) {
            if (a[idx] >= a[to])
                DSU.Join (idx, to), DSU2.Join (idx, to);
        }
        larger[idx] = DSU.Find_Larger(idx);
    }
    reb (i, n, 1) {
        static vector<int> vec; vec.clear();
        while (b[i].fs == b[i - 1].fs) vec.push_back(b[i--].se);
        vec.push_back(b[i].se);
        iter (&id, vec) {
//            cout << id<<": "<<larger[id]<<" "<<DSU2.tot[DSU2.Find(id)] <<"\n";
            if (larger[id] == -1 || (DSU2.tot[DSU2.Find(id)] >= a[larger[id]] && Ans[larger[id]] == 1)) {
                Ans[id] = 1;
            }
            else Ans[id] = 0;
        }
        iter (&id, vec) iter (&to, ke[id]) {
            if (a[id] >= a[to])
                DSU2.roll_back();
        }
    }
    rep (i ,1, n) cout << Ans[i];
}
#define file(name) freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);
int main () {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

//    file ("fbuy");
    int num_Test = 1;
//    cin >> num_Test;
    while (num_Test--)
        solution();
}
/*
7
1 2 4
2 3 12
3 4 2
4 5 48
5 6 2
6 7 123

*/

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