Submission #66132

#	Time	Username	Problem	Language	Result	Execution time	Memory
66132		Benq	Circle selection (APIO18_circle_selection)	C++11	100 / 100	2157 ms	438336 KiB

circle_selection

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 300001;

const int CON = 1000000000;
int n, r[MX], ans[MX];
pi p[MX];
set<pi> S;
map<int,int> m; vi rm;
vpi tmp[MX];

ll sq(ll x) { return x*x; }
ll dist(pi a, pi b) { a.f -= b.f, a.s -= b.s; return (ll)a.f*a.f+(ll)a.s*a.s; }
bool inter(int a, int b) { return dist(p[a],p[b]) <= sq(r[a]+r[b]); }

void init() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> n;
    FOR(i,1,n+1) {
        //p[i].f = rand() % (2*CON);
        //p[i].s = rand() % (2*CON);
        //r[i] = rand() % CON+1;
        cin >> p[i].f >> p[i].s >> r[i];
        p[i].f += CON; p[i].s += CON;
        S.insert({r[i],-i});
    }
}

ll crad = INF;

void del(int x, int e) { ans[x] = e; S.erase({r[x],-x}); }

pi getPos(int x) { return {p[x].f/crad,p[x].s/crad}; }

void recalc() {
    F0R(i,sz(m)) tmp[i].clear();
    m.clear(), rm.clear();
    FOR(i,1,n+1) if (!ans[i]) m[getPos(i).f] = 0;
    for (auto& a: m) { a.s = sz(rm); rm.pb(a.f); }
    FOR(i,1,n+1) if (!ans[i]) {
        pi P = getPos(i);
        tmp[m[P.f]].pb({P.s,i});
    }
    F0R(i,sz(m)) sort(all(tmp[i]));
}

void solve() {
    pi x = *S.rbegin(); x.s *= -1; 
    if (2*x.f <= crad) { crad = x.f; recalc(); }
    
    pi pos = getPos(x.s);
    
    int z = 0;
    for (int t = lb(all(rm),pos.f-2)-rm.begin(); 
        t < sz(rm) && abs(rm[t]-pos.f) <= 2; t ++) 
        for (int t2 = lb(all(tmp[t]),mp(pos.s-2,-MOD))-tmp[t].begin(); 
            t2 < sz(tmp[t]) && abs(tmp[t][t2].f-pos.s) <= 2; t2++) {
            if (!ans[tmp[t][t2].s] && inter(x.s,tmp[t][t2].s)) {
                del(tmp[t][t2].s,x.s);
                z ++;
            }
            // if (x.s == 3905) cout << "HUH " << t << " " << t2 << " " << tmp[t][t2].s << "\n";
        }
            
    /*if (z == 0) {
        cout << "OOPS " << inter(x.s,x.s) << "\n";
        cout << "HUH " << x.s << " " << p[x.s].f << " " << p[x.s].s << " " << ans[x.s] << " " << r[x.s] << "\n";
        cout << pos.f << " " << pos.s << " " << crad << "\n";
        cout << m[pos.f] << "\n";
        cout << lb(all(rm),pos.f-2)-rm.begin() << "\n";
        exit(0);
    }*/
}

int main() {
    init();
    while (sz(S)) solve();
    FOR(i,1,n+1) cout << ans[i] << " ";
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 30 / 30
• Subtask 6: 13 / 13