Submission #723487

#	Time	Username	Problem	Language	Result	Execution time	Memory
723487		Charizard2021	Stranded Far From Home (BOI22_island)	C++17	100 / 100	468 ms	49740 KiB

island

#include <bits/stdc++.h>
using namespace std;
struct DSU {
	vector<long long> e;
	DSU(long long N) { e = vector<long long>(N, -1); }
	long long get(long long x) { return e[x] < 0 ? x : e[x] = get(e[x]); }

	bool same_set(long long a, long long b) { return get(a) == get(b); }

	long long size(long long x) { return -e[get(x)]; }

	bool unite(long long x, long long y, vector<long long> &strength) {  // union by size
		x = get(x), y = get(y);
		if (x == y) return false;
		if (e[x] > e[y]) swap(x, y);
		e[x] += e[y]; e[y] = x;
        strength[x] += strength[y];
		return true;
	}
};
void dfs(long long u, long long works, vector<long long> &winnable, vector<vector<long long> > &val){
	winnable[u] &= works;
	for(long long v : val[u]){
        dfs(v, winnable[u], winnable, val);
    }
}
int main(){
    long long n, m;
    cin >> n >> m;
    long long arr[n];
    for(long long i = 0; i < n; i++){
        cin >> arr[i];
    }
    vector<long long> adj[n];
    for(long long i = 0; i < m; i++){
        long long a, b;
        cin >> a >> b;
        a--;
        b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    DSU dsu(n);
	vector<long long> winnable(n, 1);
    vector<bool> visited(n, false);
    vector<long long> inserted(n);
    vector<long long> comp(n);
	vector<long long> strength(n);
	vector<vector<long long> > mark(n);
	vector<pair<long long, long long> > order(n);
	for(long long i = 0; i < n; i++){
		strength[i] = arr[i];
		order[i] = make_pair(arr[i], i);
	}
	sort(order.begin(), order.end());
	for(auto t : order){
		long long u = t.second;
		for(long long v : adj[u]){
            if(inserted[v]){
                long long w = comp[dsu.get(v)];
                if(strength[dsu.get(v)] < arr[u]){
                    winnable[w] = 0;
                }
                if(!visited[w]){
                    mark[u].push_back(w);
                    visited[w] = true;
                }
            }
		}
		for(long long v : adj[u]){
            if(inserted[v]){
                visited[comp[dsu.get(v)]] = false;
            }
        }
		for(long long v : adj[u]){
            if(inserted[v]){
                dsu.unite(u, v, strength);
            }
        }
		comp[dsu.get(u)] = u;
		inserted[u] = 1;
	}
	dfs(order[n - 1].second, 1, winnable, mark);
	for(long long i = 0; i < n; i++){
        cout << winnable[i];
    }
	cout << "\n";
}

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