Submission #1097883

# Submission time Handle Problem Language Result Execution time Memory
1097883 2024-10-08T14:04:03 Z Requiem Circle selection (APIO18_circle_selection) C++17
57 / 100
1155 ms 159384 KB
#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fast ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#define MOD 1000000007
#define inf 1e18
#define fi first
#define se second
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORD(i,a,b) for(int i=a;i>=b;i--)
#define sz(a) ((int)(a).size())
#define endl '\n'
#define pi 3.14159265359
#define TASKNAME "circlesec"
using namespace std;
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
typedef pair<int,int> ii;
typedef pair<int,ii> iii;
typedef vector<int> vi;
/**
Cho n đường tròn, đường tròn thứ i: có tâm (xi, yi) và bán kính ri.

Ta có 1 thuật toán:
- Tìm đường tròn có bán kính lớn nhất.
- Xóa đường tròn đó và những đường tròn giao với nó.
- Lặp lại bước 1 và 2 cho đến khi không còn đường tròn nào.

Ta gọi đường tròn i bị loại bởi đường tròn j nếu như khi đường tròn j bị loại ở bước 1 thì đường tròn i sẽ bị loại ở bước 2.

subtask 1: n <= 5000. O(N^2)
subtask 2: n <= 3e5. yi = 0, bài toán đưa về khoảng. Giả sử cho n đoạn [li, ri], ta sẽ xóa đoạn lớn nhất xong tìm những thằng
giao với đoạn đó và loại nó ra.

Subtask này đơn giản ta sweep qua các đoạn, với mỗi đoạn.
Ta lưu 3 cái set. Mỗi set sẽ sort theo 1 thông số li, ri, và radius.

Ta có nhận xét là những đoạn có l nằm trong [l, r] sẽ bị xóa xổ ở cả 3. Khi này, độ phức tạp chỉ là O(N log N) khi mỗi phần
tử chỉ được xóa 1 lần.

subtask 3: n <= 3e5, mỗi đường tròn chỉ giao với 1 đường tròn khác.
2 đường tròn giao nhau khi d(O1, O2) <= R1 + R2.

subtask 4: n <= 3e5, mỗi đường tròn có cùng bán kính.

**/

const int MAXN = 5e5 + 9;
struct Circle{
    int x, y, r, id;
    Circle(int _x = 0, int _y = 0, int _r = 0, int _id = 0): x(_x), y(_y), r(_r), id(_id) {}

    bool operator * (const Circle &other){
        return (x - other.x) * (x - other.x) + (y - other.y) * (y - other.y) <= (r + other.r) * (r + other.r);
    }
} circle[MAXN];

struct DSU{
    vector<int> lab;

    int small_to_large = 1;
    int path_compression = 1;

    DSU(int _sz = 0, int _small_to_large = 1, int _path_compression = 1){
        small_to_large = _small_to_large;
        path_compression = _path_compression;
        lab.resize(_sz + 1, -1);
    }

    int root(int u){
        if (path_compression)  return ((lab[u] < 0) ? u : lab[u] = root(lab[u]));
        return root(lab[u]);
    }

    void unite(int u, int v){
        u = root(u);
        v = root(v);
        if (u != v){
            if (lab[u] > lab[v] and small_to_large) swap(u, v);
            lab[u] += lab[v];
            lab[v] = u;
        }
    }
};
int n;

bool deleted[MAXN];
int answer[MAXN];
namespace subtask1{
    bool check(){
        return n <= 5000;
    }

    void solve(){
        memset(deleted, 0, sizeof(deleted));

        FOR(i, 1, n){
            int delId = 0, maxR = 0;

            FOR(j, 1, n){
                if (deleted[j]) continue;
                if (maximize(maxR, circle[j].r)) delId = j;
            }

//            cout << delId << endl;
            FOR(j, 1, n){
                if (!deleted[j] and circle[delId] * circle[j]) {
                    deleted[j] = true;
                    answer[j] = delId;
//                    cout << j << ' ';
                }
            }
//            cout << endl;
        }

        FOR(i, 1, n){
            cout << answer[i] << ' ';
        }
        cout << endl;

    }
}
namespace subtask2{
    bool check(){
        FOR(i,1 , n){
            if (circle[i].y != 0) return false;
        }
        return n <= 300000;
    }

    struct cmp1{
        bool operator () (const Circle &a, const Circle &b) const{
            if (a.x == b.x) {
                if (a.y == b.y) {
                    if (a.r == b.r) return a.id < b.id;
                    return a.r < b.r;
                }
                return a.y < b.y;
            }
            return a.x < b.x;
        }
    };

    struct cmp2{
        bool operator () (const Circle &a, const Circle &b) const{
            if (a.y == b.y) {
                if (a.x == b.x) {
                    if (a.r == b.r) return a.id < b.id;
                    return a.r < b.r;
                }
                return a.x < b.x;
            }
            return a.y < b.y;
        }
    };

    struct cmp3{
        bool operator () (const Circle &a, const Circle &b) const{
            if (a.r == b.r) {
                if (a.id == b.id) {
                    if (a.y == b.y) return a.x < b.x;
                    return a.y < b.y;
                }
                return a.id > b.id;
            }
            return a.r < b.r;
        }
    };

    set<Circle, cmp1> sortX;
    set<Circle, cmp2> sortY;
    set<Circle, cmp3> sortR;

    void solve(){
        FOR(i, 1, n){
            int x = circle[i].x;
            circle[i].x = x - circle[i].r;
            circle[i].y = x + circle[i].r;
//            cout << circle[i].x << ' ' << circle[i].y << ' ' << circle[i].r << endl;
            sortX.insert(circle[i]);
            sortY.insert(circle[i]);
            sortR.insert(circle[i]);
        }
        vector<Circle> eraseList;

        while (sortR.size() > 0){
            eraseList.clear();
            Circle ToErase = *sortR.rbegin();
            int L = ToErase.x;
            int R = ToErase.y;
//            cerr << ToErase.id << ' ' << endl;

            auto s1 = sortX.lower_bound(Circle(L, -inf, -inf, -inf));
            while(s1 != sortX.end() and (*s1).x <= R){
                eraseList.pb(*s1);
//                cerr << "X: " << (*s1).x << ' ' << (*s1).id << endl;
                s1++;
            }

            auto s2 = sortY.lower_bound(Circle(-inf, L, -inf, -inf));
            while(s2 != sortY.end() and (*s2).y <= R){
//                cerr << "Y: " << (*s2).y << ' ' << (*s2).id << endl;

                eraseList.pb(*s2);
                s2++;
            }
            for(auto p: eraseList){
                answer[p.id] = ToErase.id;
                auto it1 = sortX.find(p);
                auto it2 = sortY.find(p);
                auto it3 = sortR.find(p);
//                cout << p.id << ' ';
                if (it1 != sortX.end()) sortX.erase(it1);
                if (it2 != sortY.end()) sortY.erase(it2);
                if (it3 != sortR.end()) sortR.erase(it3);
            }
//            cout << endl;
        }

        FOR(i, 1, n){
            cout << answer[i] << ' ';
        }
        cout << endl;
    }
}

namespace subtask3{
    bool check(){
        return true;
    }

    struct event{
        int x, id, type;
        event(int _x = 0, int _id = 0, int _type = 0): x(_x), id(_id), type(_type) {}
        //1: them
        //2: loai bo

        bool operator < (const event &other) const{
            if (x == other.x){
                if (type == other.type){
                    return id < other.id;
                }
                return type < other.type;
            }
            return x < other.x;
        }

    };

    struct cmp{
        bool operator() (const ii &a, const ii &b) const{
            return (a.fi == b.fi) ? (a.se > b.se) : (a.fi < b.fi);
        }
    };
    //moi duong tron chi giao voi toi da 1 duong tron khac.
    int other[MAXN];
    vector<event> events; //chua pair(x, i) la event.
    multiset<ii> listY;
    multiset<ii, cmp> sortR;
    void solve(){
        FOR(i, 1, n){
            sortR.insert(ii(circle[i].r, i));
            events.pb(event(circle[i].x - circle[i].r, i, 1));
            events.pb(event(circle[i].x - circle[i].r, i, 3));
            events.pb(event(circle[i].x, i, 3));
            events.pb(event(circle[i].x + circle[i].r, i, 3));
            events.pb(event(circle[i].x + circle[i].r + 1, i, 2));
        }
        sort(events.begin(),events.end());

        for(auto e: events){
            if (e.type == 1) {
                int addId = e.id;
                listY.insert(ii(circle[addId].y, addId));
            }
            else if (e.type == 3){
                int addId = e.id;
                auto it = listY.lower_bound(ii(circle[addId].y, addId));
                if (it != listY.end()){
                    auto nxt = next(it);
                    if (nxt != listY.end() and circle[addId] * circle[(*nxt).se]) {
                        other[addId] = (*nxt).se;
                        other[(*nxt).se] = addId;
                    }
                }

                if (it != listY.begin()){
                    auto prv = prev(it);
                    if (circle[addId] * circle[(*prv).se]) {
                        other[addId] = (*prv).se;
                        other[(*prv).se] = addId;
                    }
                }
            }

            else{
                int delId = e.id;
//                cout << "DEL: " << delId << endl;

                listY.erase(listY.find(ii(circle[delId].y, delId)));
            }
        }

        while(!sortR.empty()){
            auto it = *sortR.rbegin();

            int id = it.se;
            answer[id] = id;
//            cout << circle[id].id << endl;

            sortR.erase(sortR.find(it));

            if (other[id] != 0) {
                answer[other[id]] = id;
                ii tmp = ii(circle[other[id]].r, circle[other[id]].id);
                if (sortR.find(tmp) != sortR.end()) sortR.erase(sortR.find(tmp) );
            }
        }
//        FOR(i, 1, n){
//            cout << other[i] << ' ';
//        }
//        cout << endl;

        FOR(i, 1, n){
            cout << answer[i] << ' ';
        }
    }
}

namespace subtask4{
    bool check(){
        FOR(i,1 , n){
            if (circle[i].r != circle[1].r) return false;
        }
        return true;
    }

    /**
    Idea cua sub nay la: ta se chia
    truc thanh cac o r * r.
    luc nay, ta chi can xet hinh trong co tam nam trong vung hinh vuong 5r * 5r.
    **/

    int maxR = 0;
    vector<int> listX;

    int getVal(vector<int> &listVal, int x){
        return lower_bound(listVal.begin(), listVal.end(), x) - listVal.begin();
    }


    struct cmpR{
        bool operator() (const ii &a, const ii &b) const{
            return (a.fi == b.fi) ? (a.se > b.se) : (a.fi < b.fi);
        }
    };

    multiset<ii, cmpR> sortR;  //chua ii(r, i)

    struct gridding{
        vector<ii> grid;
        DSU remaining;

        void add(ii a){  //them 1 phan tu
            grid.pb(a);
        }

        void refine(){
            sort(grid.begin(), grid.end());
            remaining = DSU(grid.size() + 2, 0, 1);
        }

        int lb(ii x){
            return lower_bound(grid.begin(), grid.end(), x) - grid.begin() ;
        }

        void toDelete(int l){  //xoa 1 doan [l, r]
            remaining.unite(l + 1, l);
        }
    };

    gridding grid[MAXN];  //chua ii(y, i)
    vector<int> toErase;
    void solve(){
        maxR = circle[1].r;
        FOR(i, 1, n){
            sortR.insert(ii(circle[i].r, circle[i].id));
        }

        FOR(i, 1, n){
            listX.pb(circle[i].x / maxR);
        }

        sort(listX.begin(), listX.end());
        listX.erase(unique(listX.begin(), listX.end()), listX.end());
//
        FOR(i, 1, n){
            int x = getVal(listX, circle[i].x / maxR);
            grid[x].add(ii(circle[i].y / maxR, i));
        }
        FOR(i, 0, MAXN - 1){
            grid[i].refine();
        }
//        FOR(i, 0, 2){
//            for(auto p: grid[i].grid){
//                cout << p.fi << ' ' << p.se << endl;
//            }
//            cout << endl;
//        }
//        cout << endl;
        while(!sortR.empty()){
            auto it = *sortR.rbegin();
            int id = it.se;
            answer[id] = id;
//            cout << id << endl;

            int discreteX = circle[id].x / maxR;
            int discreteY = circle[id].y / maxR;
//            cout << discreteX << ' ' << discreteY << endl;

            FOR(nx, discreteX - 2, discreteX + 2){
                int valX = getVal(listX, nx);
                toErase.clear();

                if (valX != listX.size() and listX[valX] == nx){

                    int id1 = grid[valX].lb(ii(discreteY - 2, -inf));
                    int cnt = 0;

//                    cout << "CHOSE: ";
                    for(;id1 < grid[valX].grid.size() and grid[valX].grid[id1].fi <= discreteY + 2;){
                        id1 = grid[valX].remaining.root(id1);
                        if (id1 >= grid[valX].grid.size()) continue;
                        int idC = grid[valX].grid[id1].se;
//                        cout << idC << ' ';
//                        cnt++;
                        if (circle[idC] * circle[id]) {
                            toErase.pb(idC);
                            answer[idC] = id;
                            grid[valX].toDelete(id1);
                        }
                        else id1++;
//                        if (cnt > n) break;
                    }
//                    cout << endl;
//
                    for(auto id: toErase){
                        ii t1 = ii(circle[id].r, circle[id].id);
                        if (sortR.find(t1) != sortR.end())
                            sortR.erase(sortR.find(t1));
                    }
                }
            }
        }

        FOR(i, 1, n){
            cout << answer[i] << ' ';
        }
        cout << endl;

    }
}

namespace subtask56{
    bool check(){
        return true;
    }

    /**
    Quy trình:
    Như subtask 4 nhưng ta sẽ chia maxR làm đôi mỗi khi curMaxR < maxR.
    Ta sẽ thêm 1 cái log vào kết quả.
    Độ phức tạp của ta có thể là O(N log N)
    **/
    void solve(){

    }
}


void input(){
    cin >> n;
    FOR(i, 1, n){
        cin >> circle[i].x >> circle[i].y >> circle[i].r;
        circle[i].id = i;
    }

    if (subtask1::check()) return subtask1::solve();
    if (subtask2::check()) return subtask2::solve();
    if (subtask4::check()) return subtask4::solve();

    if (subtask3::check()) return subtask3::solve();
}
main()
{
    fast;
    if (fopen(TASKNAME".inp","r")){
        freopen(TASKNAME".inp","r",stdin);
        freopen(TASKNAME".out","w",stdout);
    }

    input();

}
/**
Warning:
Cận lmao
Code imple thiếu case nào không.
Limit.
**/

Compilation message

circle_selection.cpp: In function 'void subtask4::solve()':
circle_selection.cpp:425:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  425 |                 if (valX != listX.size() and listX[valX] == nx){
      |                     ~~~~~^~~~~~~~~~~~~~~
circle_selection.cpp:431:30: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  431 |                     for(;id1 < grid[valX].grid.size() and grid[valX].grid[id1].fi <= discreteY + 2;){
      |                          ~~~~^~~~~~~~~~~~~~~~~~~~~~~~
circle_selection.cpp:433:33: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  433 |                         if (id1 >= grid[valX].grid.size()) continue;
      |                             ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
circle_selection.cpp:428:25: warning: unused variable 'cnt' [-Wunused-variable]
  428 |                     int cnt = 0;
      |                         ^~~
circle_selection.cpp: At global scope:
circle_selection.cpp:494:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  494 | main()
      | ^~~~
circle_selection.cpp: In function 'int main()':
circle_selection.cpp:498:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  498 |         freopen(TASKNAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
circle_selection.cpp:499:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  499 |         freopen(TASKNAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 40 ms 63480 KB Output is correct
2 Correct 39 ms 63580 KB Output is correct
3 Correct 39 ms 63372 KB Output is correct
4 Correct 40 ms 63316 KB Output is correct
5 Correct 38 ms 63416 KB Output is correct
6 Correct 39 ms 63448 KB Output is correct
7 Correct 39 ms 63332 KB Output is correct
8 Correct 38 ms 63572 KB Output is correct
9 Correct 39 ms 63568 KB Output is correct
10 Correct 42 ms 63568 KB Output is correct
11 Correct 37 ms 63564 KB Output is correct
12 Correct 35 ms 63524 KB Output is correct
13 Correct 40 ms 63572 KB Output is correct
14 Correct 38 ms 63568 KB Output is correct
15 Correct 41 ms 63576 KB Output is correct
16 Correct 41 ms 63568 KB Output is correct
17 Correct 46 ms 63572 KB Output is correct
18 Correct 46 ms 63572 KB Output is correct
19 Correct 70 ms 63568 KB Output is correct
20 Correct 72 ms 63568 KB Output is correct
21 Correct 75 ms 63732 KB Output is correct
22 Correct 92 ms 63568 KB Output is correct
23 Correct 95 ms 63744 KB Output is correct
24 Correct 92 ms 63568 KB Output is correct
25 Correct 92 ms 63580 KB Output is correct
26 Correct 92 ms 63580 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 994 ms 158852 KB Output is correct
2 Correct 1093 ms 152744 KB Output is correct
3 Correct 1155 ms 157096 KB Output is correct
4 Correct 1128 ms 159384 KB Output is correct
5 Correct 1016 ms 142908 KB Output is correct
6 Correct 944 ms 142904 KB Output is correct
7 Correct 987 ms 142932 KB Output is correct
8 Correct 972 ms 142884 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 43 ms 63568 KB Output is correct
2 Correct 164 ms 86488 KB Output is correct
3 Correct 493 ms 133992 KB Output is correct
4 Correct 502 ms 133920 KB Output is correct
5 Correct 555 ms 133920 KB Output is correct
6 Correct 302 ms 99372 KB Output is correct
7 Correct 150 ms 82392 KB Output is correct
8 Correct 60 ms 67832 KB Output is correct
9 Correct 491 ms 133928 KB Output is correct
10 Correct 589 ms 134332 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 599 ms 106912 KB Output is correct
2 Correct 579 ms 110268 KB Output is correct
3 Correct 454 ms 105660 KB Output is correct
4 Correct 609 ms 109908 KB Output is correct
5 Correct 595 ms 110516 KB Output is correct
6 Correct 456 ms 104372 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 40 ms 63480 KB Output is correct
2 Correct 39 ms 63580 KB Output is correct
3 Correct 39 ms 63372 KB Output is correct
4 Correct 40 ms 63316 KB Output is correct
5 Correct 38 ms 63416 KB Output is correct
6 Correct 39 ms 63448 KB Output is correct
7 Correct 39 ms 63332 KB Output is correct
8 Correct 38 ms 63572 KB Output is correct
9 Correct 39 ms 63568 KB Output is correct
10 Correct 42 ms 63568 KB Output is correct
11 Correct 37 ms 63564 KB Output is correct
12 Correct 35 ms 63524 KB Output is correct
13 Correct 40 ms 63572 KB Output is correct
14 Correct 38 ms 63568 KB Output is correct
15 Correct 41 ms 63576 KB Output is correct
16 Correct 41 ms 63568 KB Output is correct
17 Correct 46 ms 63572 KB Output is correct
18 Correct 46 ms 63572 KB Output is correct
19 Correct 70 ms 63568 KB Output is correct
20 Correct 72 ms 63568 KB Output is correct
21 Correct 75 ms 63732 KB Output is correct
22 Correct 92 ms 63568 KB Output is correct
23 Correct 95 ms 63744 KB Output is correct
24 Correct 92 ms 63568 KB Output is correct
25 Correct 92 ms 63580 KB Output is correct
26 Correct 92 ms 63580 KB Output is correct
27 Incorrect 56 ms 66296 KB Output isn't correct
28 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 40 ms 63480 KB Output is correct
2 Correct 39 ms 63580 KB Output is correct
3 Correct 39 ms 63372 KB Output is correct
4 Correct 40 ms 63316 KB Output is correct
5 Correct 38 ms 63416 KB Output is correct
6 Correct 39 ms 63448 KB Output is correct
7 Correct 39 ms 63332 KB Output is correct
8 Correct 38 ms 63572 KB Output is correct
9 Correct 39 ms 63568 KB Output is correct
10 Correct 42 ms 63568 KB Output is correct
11 Correct 37 ms 63564 KB Output is correct
12 Correct 35 ms 63524 KB Output is correct
13 Correct 40 ms 63572 KB Output is correct
14 Correct 38 ms 63568 KB Output is correct
15 Correct 41 ms 63576 KB Output is correct
16 Correct 41 ms 63568 KB Output is correct
17 Correct 46 ms 63572 KB Output is correct
18 Correct 46 ms 63572 KB Output is correct
19 Correct 70 ms 63568 KB Output is correct
20 Correct 72 ms 63568 KB Output is correct
21 Correct 75 ms 63732 KB Output is correct
22 Correct 92 ms 63568 KB Output is correct
23 Correct 95 ms 63744 KB Output is correct
24 Correct 92 ms 63568 KB Output is correct
25 Correct 92 ms 63580 KB Output is correct
26 Correct 92 ms 63580 KB Output is correct
27 Correct 994 ms 158852 KB Output is correct
28 Correct 1093 ms 152744 KB Output is correct
29 Correct 1155 ms 157096 KB Output is correct
30 Correct 1128 ms 159384 KB Output is correct
31 Correct 1016 ms 142908 KB Output is correct
32 Correct 944 ms 142904 KB Output is correct
33 Correct 987 ms 142932 KB Output is correct
34 Correct 972 ms 142884 KB Output is correct
35 Correct 43 ms 63568 KB Output is correct
36 Correct 164 ms 86488 KB Output is correct
37 Correct 493 ms 133992 KB Output is correct
38 Correct 502 ms 133920 KB Output is correct
39 Correct 555 ms 133920 KB Output is correct
40 Correct 302 ms 99372 KB Output is correct
41 Correct 150 ms 82392 KB Output is correct
42 Correct 60 ms 67832 KB Output is correct
43 Correct 491 ms 133928 KB Output is correct
44 Correct 589 ms 134332 KB Output is correct
45 Correct 599 ms 106912 KB Output is correct
46 Correct 579 ms 110268 KB Output is correct
47 Correct 454 ms 105660 KB Output is correct
48 Correct 609 ms 109908 KB Output is correct
49 Correct 595 ms 110516 KB Output is correct
50 Correct 456 ms 104372 KB Output is correct
51 Incorrect 56 ms 66296 KB Output isn't correct
52 Halted 0 ms 0 KB -