Codeforces - Clique Problem

题目链接：Codeforces - Clique Problem

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我们令 xi >= xj则：
xi-xj>=wi+wj -> xi-wi>=xj+wj
令：li=xi-wi,ri=xi+wi
然后就是一个线段区间覆盖问题了，贪心即可。

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AC代码：

#pragma GCC optimize("-Ofast","-funroll-all-loops")
#include<bits/stdc++.h>
//#define int long long
using namespace std;
const int N=2e5+10;
int n,res,ed=-1e9;
struct node{int l,r;}t[N];
int cmp(node a,node b){return a.r<b.r;}
signed main(){
	cin>>n;
	for(int i=1,x,w;i<=n;i++)	scanf("%d %d",&x,&w),t[i]={x-w,x+w};
	sort(t+1,t+1+n,cmp);
	for(int i=1;i<=n;i++)	if(t[i].l>=ed)	res++,ed=t[i].r;
	cout<<res;
	return 0;
}