Submission #1292477

#	Time	Username	Problem	Language	Result	Execution time	Memory
1292477		chaitanyamehta	Lost Array (NOI19_lostarray)	C++20	0 / 100	2 ms	332 KiB

lostarray

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

struct DSU {
    vector<int> par, sz;
    void init(int n) {
        par.resize(n + 1);
        sz.resize(n + 1, 1);
        for (int i = 1; i <= n; i++) par[i] = i;
    }
    int find(int u) {
        return par[u] == u ? u : par[u] = find(par[u]);
    }
    bool unite(int u, int v) {
        u = find(u); v = find(v);
        if (u == v) return false;
        if (sz[u] < sz[v]) swap(u, v);
        par[v] = u;
        sz[u] += sz[v];
        return true;
    }
};

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n, q;
    cin >> n >> q;
    
    DSU dsu;
    dsu.init(n);
    
    // Store attraction between component roots: {smaller, larger}
    set<pair<int, int>> attract;
    
    while (q--) {
        char type;
        cin >> type;
        int x, y;
        cin >> x >> y;
        
        int px = dsu.find(x);
        int py = dsu.find(y);
        
        if (type == 'U') {
            // Merge components
            // Before merging, move attractions from old roots if needed
            dsu.unite(x, y);
        }
        else if (type == 'A') {
            // Add attraction between current components
            if (px == py) continue; // same component, ignore?
            if (px > py) swap(px, py);
            attract.insert({px, py});
        }
        else if (type == 'Q') {
            if (px == py) {
                cout << "R\n";
            }
            else {
                if (px > py) swap(px, py);
                if (attract.count({px, py})) {
                    cout << "A\n";
                }
                else {
                    cout << "?\n";
                }
            }
        }
    }
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 6
• Subtask 3: 0 / 20
• Subtask 4: 0 / 21
• Subtask 5: 0 / 48