Submission #968056

#	Time	Username	Problem	Language	Result	Execution time	Memory
968056		socpite	Circle selection (APIO18_circle_selection)	C++14	19 / 100	3054 ms	41008 KiB

circle_selection

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

const int maxn = 3e5+5;
const int INF = 1e9+5;

pair<int, int> pt[maxn];

bool cmpx(int a, int b){
    return pt[a].first < pt[b].first; 
}

bool cmpy(int a, int b){
    return pt[a].second < pt[b].second;
}

int n;
int st[4*maxn], Lx[4*maxn], Rx[4*maxn], Ly[4*maxn], Ry[4*maxn];
int pid[4*maxn];
int pos[maxn];
int removed[maxn];
int R[maxn];

bool cmpr(int a, int b){
    return R[a] != R[b] ? R[a] > R[b] : a < b; 
}

bool check(int a, int b){
    return 1LL*(pt[a].first - pt[b].first)*(pt[a].first - pt[b].first) + 1LL*(pt[a].second - pt[b].second)*(pt[a].second - pt[b].second) - 1LL*(R[a] + R[b])*(R[a] + R[b])  <= 0;
}

void build(vector<int> vec, int dep, int id){
    Lx[id] = Ly[id] = INF;
    if(vec.empty())return;
    sort(vec.begin(), vec.end(), dep&1 ? cmpx : cmpy);
    int mid = vec.size()/2;
    pid[id] = vec[mid];
    pos[vec[mid]] = id;
    vector<int> v1, v2;
    for(int i = 0; i < vec.size(); i++){
        if(i < mid)v1.push_back(vec[i]);
        if(i > mid)v2.push_back(vec[i]);
    }
    for(auto v: vec){
        st[id] = max(st[id], R[v]);
        Lx[id] = min(Lx[id], pt[v].first);
        Ly[id] = min(Ly[id], pt[v].second);
        Rx[id] = max(Rx[id], pt[v].first);
        Ry[id] = max(Ry[id], pt[v].second);
    }
    build(v1, dep^1, id<<1);
    build(v2, dep^1, id<<1|1);
}

void recalc(int id){
    st[id] = max(st[id<<1], st[id<<1|1]);
    Lx[id] = min(Lx[id<<1], Lx[id<<1|1]);
    Ly[id] = min(Ly[id<<1], Ly[id<<1|1]);
    Rx[id] = max(Rx[id<<1], Rx[id<<1|1]);
    Ry[id] = max(Ry[id<<1], Ry[id<<1|1]);
    if(pid[id]){
        st[id] = max(st[id], R[pid[id]]);
        Lx[id] = min(Lx[id], pt[pid[id]].first);
        Ly[id] = min(Ly[id], pt[pid[id]].second);
        Rx[id] = max(Rx[id], pt[pid[id]].first);
        Ry[id] = max(Ry[id], pt[pid[id]].second);
    }
}

void remove(int x){
    int id = pos[x];
    pid[id] = 0;
    while(id){
        recalc(id);
        id >>= 1;
    }
}

void search(int x, int dep, int id){
    if(pid[id]){
        if(check(x, pid[id])){
            removed[pid[id]] = x;
            remove(pid[id]);
        }
    }
    if(st[id<<1] && (dep&1 ? (pt[x].first < Rx[id<<1] || pt[x].first - Rx[id<<1] <= R[x] + st[id<<1]) :
                            (pt[x].second < Ry[id<<1] || pt[x].second - Ry[id<<1] <= R[x] + st[id<<1])))search(x, dep^1, id<<1);
    if(st[id<<1|1] && (dep&1 ? (pt[x].first > Lx[id<<1|1] || Lx[id<<1|1] - pt[x].first <= R[x] + st[id<<1|1]) :
                            (pt[x].second > Ly[id<<1|1] || Ly[id<<1|1] - pt[x].second <= R[x] + st[id<<1|1])))search(x, dep^1, id<<1|1);
}

vector<int> bad;


int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    vector<int> vec(n);
    iota(vec.begin(), vec.end(), 1);
    for(int i = 1; i <= n; i++){
        cin >> pt[i].first >> pt[i].second >> R[i];
    }
    build(vec, 0, 1);
    sort(vec.begin(), vec.end(), cmpr);
    for(auto v: vec){
        if(removed[v])continue;
        search(v, 0, 1);
    }
    for(int i = 1; i <= n; i++)cout << removed[i] << " ";
}

Compilation message (stderr)

circle_selection.cpp: In function 'void build(std::vector<int>, int, int)':
circle_selection.cpp:40:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |     for(int i = 0; i < vec.size(); i++){
      |                    ~~^~~~~~~~~~~~

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