CF607A Chain Reaction

Lisa

显然的dp，只需要再二分查找一下

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
int n;
struct to{
	int a;
	int b;
	friend bool operator <(to x,to y){
		return x.a<y.a;
	}
}tow[1000005];
int f[1000005];
int a[1000051];
int main(){
	scanf("%d",&n);
	for(int i=1;i<=n;++i){
		scanf("%d%d",&tow[i].a,&tow[i].b);
		a[i]=tow[i].a;
	}
	sort(tow+1,tow+n+1);
	sort(a+1,a+n+1);
	for(int i=1;i<=n;++i){
		int ff=lower_bound(a+1,a+n+1,a[i]-tow[i].b)-a-1;
		if(ff<=0){
			ff=0;
		}
		f[i]=f[ff]+1;
	}
	int ans=199999999;
	for(int i=1;i<=n;++i){
		ans=min(ans,n-f[i]);
	}
	cout<<ans;
	return 0;
}

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