C++ 代码

#include<iostream>
#include<algorithm>
#include<cmath>

using namespace std;

struct node
{
    double st,ed;
}po[1010];

bool cmp(node a,node b)
{
    return a.ed<b.ed;
}

int main()
{
    int n,d;
    cin>>n>>d;
    bool su=true;
    for(int i=0;i<n;i++)
    {
        int x,y;
        cin>>x>>y;
        if(y>d)
        {
            su=false;
            break;
        }
        auto len=sqrt(d*d-y*y);
        po[i].st=x-len;
        po[i].ed=x+len;
    }

    if(!su)
    {
        cout<<"-1"<<endl;
    }
    else
    {
        sort(po,po+n,cmp);

        int res=0;
        double last=-1e10;

        for(int i=0;i<n;i++)
        {
            if(po[i].st>last+1e-6)
            {
                res++;
                last=po[i].ed;
            }
        }
        cout<<res<<endl;
    }

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