Submission #653865

#	Time	Username	Problem	Language	Result	Execution time	Memory
653865		true22	Experimental Charges (NOI19_charges)	C++14	0 / 100	6 ms	5204 KiB

charges

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

// short forms // 
#define nl "\n"
#define pb push_back
#define f first
#define s second
#define ll long long int
#define ld long double
#define mp make_pair

#define all(x) x.begin(), x.end()

// debug // 
#define pv(x) for(auto k : x){cout << k << " ";} cout << nl;
#define pp(x) cout << x.f << " " << x.s << nl;
#define bv(x) if (x) cout << "true"; else cout << "false";
#define gp(x, y) x << " " << y 

// loop //
#define FOR(i, a, b) for(ll i = a; i <=b; i++)

// pair // 
typedef pair<ll, ll> pl;

// vector // 
typedef vector<ll> vl;
typedef vector<vl> vvl;    
typedef vector<pl> vp;

// constants // 
const ll INF = 1e17; 
const ll mod = 1e9 + 7;
const ll S = 1e5 + 5;
ll n, siz[S], link[S], eof[S];

ll find(ll a){
    ll st = a;
    while(a != link[a]) a = link[a];
    //path compression
    while(st != link[st]){
        ll tmp = link[st];
        link[st] = a;
        st = tmp;
    }
    return a;
}

bool unite(ll a, ll b){
    a = find(a);
    b = find(b);
    if (a == b) return 0;
    // union by size
    if (siz[a] < siz[b]) swap(a, b);
    siz[a] += siz[b];
    link[b] = a;
}

void set_same(ll a, ll b){ 
    /*
        1) unite the friends
        2) unite the enemies of the friends
        3) copy the link
    */
    a = find(a);
    b = find(b);
    if (siz[a] < siz[b]) swap(a, b);
    // a is the bigger set
    unite(a, b);
    if (eof[a] != -1 && eof[b] != -1)
        unite(eof[a], eof[b]);
    
    if (eof[a] == -1)
        eof[a] = eof[b];
}

void set_op(ll c1, ll c2){
    /*
        Most importantly, this is symmetric
        so the enemy of c1 is united with rep of c1 and vice versa
    */
    ll set1 = find(c1);
    ll set2 = find(c2);
    ll e = eof[set1];
    if (e == -1)
        eof[set1] = c2;
    else
        unite(e, c2);
    e = eof[set2];
    if (e == -1)
        eof[set2] = c1;
    else
        unite(e, c1);   
}

void query(ll a, ll b){
    a = find(a);
    b = find(b);
    if (a == b){
        cout << 'R' << nl;
        return; // repel
    }
    if (find(eof[a]) == b){
        cout << 'A' << nl;
        return; // attract
    }
    if (eof[a] == -1){
        cout << '?' << nl;
        return;
    }
}

void solve(){
    FOR(i, 0, S-1){
        link[i] = i;
        siz[i] = 1;
        eof[i] = -1;
    }    
    ll q;
    cin >> n >> q;
    while(q--){
        char t;
        ll a, b;
        cin >> t;
        cin >> a >> b;
        if (t == 'A'){
            set_op(a, b);
        }else if (t == 'R'){
            set_same(a, b);
        }else{
      //      cout << "for " << gp(a, b) << nl;
      //      cout << find(a) << ' ' << find(b) << nl;
            query(a, b);
        }
    }
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    ll t = 1;
    //cin >> t;
    while(t--){
        
        solve();
    }
    
    return 0;
}

Compilation message (stderr)

charges.cpp: In function 'bool unite(long long int, long long int)':
charges.cpp:58:13: warning: control reaches end of non-void function [-Wreturn-type]
   58 |     link[b] = a;
      |     ~~~~~~~~^~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 11
• Subtask 3: 0 / 14
• Subtask 4: 0 / 12
• Subtask 5: 0 / 25
• Subtask 6: 0 / 31