HDU 2073 貪心

排序+貪心

 

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <bitset>
#include <vector>
#include <cstdlib>
using namespace std;

const int MAXNUM = 105; 
struct Node
{
	int begin,end;
	Node(int a,int b):begin(a),end(b) {}
};
bool compare(const Node& n1,const Node& n2)
{
	return n1.end < n2.end;
}
bitset<MAXNUM> bset;

int main()
{
	//freopen("HDU2037.txt","r",stdin);
	int n;
	vector<Node> nodevec;
	while(scanf("%d",&n)&&n)
	{
		nodevec.clear();
		bset.reset();//all to zero
		int i = 0,tmpa,tmpb;
		while(i<n)
		{
			scanf("%d%d",&tmpa,&tmpb);
			nodevec.push_back(Node(tmpa,tmpb));
			i++;
		}
		sort(nodevec.begin(),nodevec.end(),compare);
		bset.set(0);
		int prev = 0; 
		for(int j = 1;j < nodevec.size();j++)
		{
			if(nodevec[j].begin >= nodevec[prev].end)
			{
				bset.set(j);
				prev = j;
			}
		}
		cout<<bset.count()<<endl;
	}
	return 0;
}