Submission #1210693

#	Time	Username	Problem	Language	Result	Execution time	Memory
1210693		a1m4n	Circle selection (APIO18_circle_selection)	C++20	100 / 100	2137 ms	198180 KiB

circle_selection

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("fast-math")
#pragma GCC optimize("Ofast") 
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("O2")
static const int K = 31;
static const int INF = 1000000000;
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    int *x = new int[n];
    int *y = new int[n];
    int *r = new int[n];
    int *ans = new int[n]();
    vector<ll> pw;
    for(ll v = 1; v <= 2LL*INF; v *= 10) pw.push_back(v);
    int m = pw.size();
    vector<unordered_map<ll, vector<int>>> mp(m);
    for(int i = 0; i < n; i++){
        cin >> x[i] >> y[i] >> r[i];
        x[i] += INF;
        y[i] += INF;
        for(int j = 0; j < m; j++){
            ll bx = x[i] / pw[j];
            ll by = y[i] / pw[j];
            ll key = (bx << K) | by;
            mp[j][key].push_back(i);
        }
    }
    vector<int> ord(n);
    iota(ord.begin(), ord.end(), 0);
    sort(ord.begin(), ord.end(), [&](int a,int b){
        return (r[a] > r[b]) || (r[a] == r[b] && a < b);
    });
    auto overlap = [&](int i,int j){
        ll dx = ll(x[i]) - x[j];
        ll dy = ll(y[i]) - y[j];
        ll R = ll(r[i]) + r[j];
        return dx*dx + dy*dy <= R*R;
    };
    for(int idx: ord){
        if(ans[idx]) continue;
        int t = 0;
        while(t < m && pw[t] < r[idx]) t++;
        ll bx = x[idx] / pw[t];
        ll by = y[idx] / pw[t];
        for(int dxg = -2; dxg <= 2; dxg++){
            for(int dyg = -2; dyg <= 2; dyg++){
                ll cx = bx + dxg;
                ll cy = by + dyg;
                ll key = (cx << K) | cy;
                auto it = mp[t].find(key);
                if(it == mp[t].end()) continue;
                auto &bucket = it->second;
                vector<int> keep;
                keep.reserve(bucket.size());
                for(int j: bucket){
                    if(ans[j]) continue;
                    if(overlap(idx,j)) ans[j] = idx+1;
                    else keep.push_back(j);
                }
                if(keep.empty()) mp[t].erase(it);
                else bucket.swap(keep);
            }
        }
    }
    for(int i = 0; i < n; i++) cout << ans[i] << ' ';
    cout << '\n';
    return 0;
}

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