【codevs3012】线段覆盖4

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
struct hp{
	int ai,bi,ci;
}a[1005];
bool cmp(hp a,hp b){
	return a.bi<b.bi;
}
const int M =1e6+2;
int n,i,j,k,maxn,f[1005];
int c[M];
int lowbit(int x){ return x&-x;}
void add(int x,int v){
	for(;x<=1e6;x+=lowbit(x)) c[x]=max(c[x],v);
}
int qq(int x){
	int t=0; 
	for(;x;x-=lowbit(x)) t=max(t,c[x]); 
	return t;
}
signed main(){
	scanf("%d",&n);
	for (i=1;i<=n;++i)
	  scanf("%d%d%d",&a[i].ai,&a[i].bi,&a[i].ci);
	sort(a+1,a+n+1,cmp);
	int ans=0;
	
	for (i=2;i<=n;++i){
		f[i]=a[i].ci; 
		
		f[i]=max(f[i],qq(a[i].ai)) ;
		add(a[i].ai,f[i]) ;
		
		ans=max(ans,f[i]) ;
	}
	cout<< ans <<endl;
}