Submission #1043448

#	Time	Username	Problem	Language	Result	Execution time	Memory
1043448		vjudge1	Circle selection (APIO18_circle_selection)	C++17	19 / 100	839 ms	61484 KiB

circle_selection

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

typedef long long ll;

const ll N = 3e5 + 10;
ll n, a[N][3], par[N];

ll dist(ll a, ll b, ll x, ll y){
    return ((x - a) * (x - a) + (y - b) * (y - b));
}

int main(){
    cin >> n;
    for (ll i = 1; i <= n; i ++)
        for (ll j = 0; j < 3; j ++)
            cin >> a[i][j];

    if (n <= 5000){
        while (1){
            ll mx = -1;
            for (ll i = 1; i <= n; i ++)
                if (!par[i] and (mx == -1 or a[i][2] > a[mx][2]))
                    mx = i;

            if (mx == -1) break;

            for (ll i = 1; i <= n; i ++)
                if (!par[i] and dist(a[i][0], a[i][1], a[mx][0], a[mx][1]) <= (a[i][2] + a[mx][2]) * (a[i][2] + a[mx][2]))
                    par[i] = mx;
        }

        for (ll i = 1; i <= n; i ++)
            cout << par[i] << " ";
        cout << endl;
        return 0;
    }

    set<pair<int, int>> st, rem;
    for (int i = 1; i <= n; i ++){
        st.insert({a[i][0] + a[i][2], i});
        st.insert({a[i][0] - a[i][2], i});
        rem.insert({-a[i][2], i});
    }

    while (rem.size()){
        int c = (*rem.begin()).second;
        rem.erase(rem.begin());

        if (par[c])
            continue;

        auto it = st.lower_bound({a[c][0] + a[c][2], n});
        while (it == st.end() or (*it).first > (a[c][0] + a[c][2]))
            it--;

        vector<int> done;
        while (1){
            int i = (*it).second;
            if (dist(a[i][0], a[i][1], a[c][0], a[c][1]) <= (a[i][2] + a[c][2]) * (a[i][2] + a[c][2])){
                par[i] = c;
                done.push_back(i);
            }
            else
                break;

            if (it == st.begin()) break;
            it--;
        }

        for (int i : done){
            st.erase({a[i][0] + a[i][2], i});
            st.erase({a[i][0] - a[i][2], i});
        }
    }

    for (int i = 1; i <= n; i ++)
        cout << par[i] << " ";
    cout << endl;
}

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 30
• Subtask 6: 0 / 13