Submission #49427

#	Time	Username	Problem	Language	Result	Execution time	Memory
49427		gs13105	Circle selection (APIO18_circle_selection)	C++17	19 / 100	1210 ms	38028 KiB

circle_selection

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <iterator>

using namespace std;

struct cir
{
    int x, y, r, i;
    bool operator <(const cir &a) const
    {
        return r != a.r ? r > a.r : i < a.i;
    }
};

cir arr[300010];
int num[300010];
int res[300010];

bool inter(const cir &a, const cir &b)
{
    return 1LL * (a.x - b.x) * (a.x - b.x) + 1LL * (a.y - b.y) * (a.y - b.y) <= 1LL * (a.r + b.r) * (a.r + b.r);
}

int main()
{
    //freopen("in", "r", stdin);
    //freopen("out", "w", stdout);

    int n, i, j;
    scanf("%d", &n);
    for(i = 1; i <= n; i++)
    {
        int x, y, r;
        scanf("%d%d%d", &x, &y, &r);
        arr[i] = { x, y, r, i };
    }

    sort(arr + 1, arr + n + 1);

    if(n <= 5000)
    {
        for(i = 1; i <= n; i++)
            if(!num[i])
                for(j = 1; j <= n; j++)
                    if(!num[j] && inter(arr[i], arr[j]))
                        num[j] = arr[i].i;

        for(i = 1; i <= n; i++)
            res[arr[i].i] = num[i];

        for(i = 1; i <= n; i++)
            printf("%d ", res[i]);
        return 0;
    }

    bool st2 = 1;
    for(i = 1; i <= n; i++)
    {
        if(arr[i].y != 0)
        {
            st2 = 0;
            break;
        }
    }

    if(st2)
    {
        set<pair<int, int>> s;
        for(i = 1; i <= n; i++)
        {
            s.insert({ arr[i].x - arr[i].r, i });
            s.insert({ arr[i].x + arr[i].r, i });
        }

        for(i = 1; i <= n; i++)
        {
            if(num[i])
                continue;

            auto it = s.lower_bound({ arr[i].x - arr[i].r, -1 });
            while(it != s.end() && it->first <= arr[i].x + arr[i].r)
            {
                int x = it->second;
                if(!num[x])
                    num[x] = arr[i].i;

                it++;
                s.erase(prev(it));
            }
        }

        for(i = 1; i <= n; i++)
            res[arr[i].i] = num[i];

        for(i = 1; i <= n; i++)
            printf("%d ", res[i]);
        return 0;
    }

    return 0;
}

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:44:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
circle_selection.cpp:48:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d", &x, &y, &r);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

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