题解

#include<stdio.h>
#include<algorithm>
using namespace std;

struct Node{
	double s,f; //注意用 double
}a[1005];

bool cmp(Node x,Node y){
	return x.s<y.s;
}

int main(){
	int n;
	double t;
	scanf("%d%lf",&n,&t);
	for(int i=0;i<n;i++){
		double b,l;
		scanf("%lf%lf",&b,&l);
		a[i].s=b-l/2; //左端点
		a[i].f=b+l/2; //右端点
	}
	sort(a,a+n,cmp);
	int ans=2; //最左与最右，初值直接赋 2
	for(int i=1;i<n;i++){
		if(a[i].s-a[i-1].f>t)ans+=2;//差距大于t
		if(a[i].s-a[i-1].f==t)ans++; //差距等于t
	}
	printf("%d",ans);
	return 0; //完结撒花
}