（算法练习）——区间贪心

P122
依然是注意结构体里面x，y的比较

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

const int maxn = 110;
struct Inteval{
	int x,y;
}I[maxn];

bool cmp(Inteval a,Inteval b){
	if(a.x != b.x) return a.x > b.x;
	else return a.y < b.y;
}

int main(){
	int n;
	while(scanf("%d",&n),n != 0){
		for(int i = 0;i <n;i++){
			scanf("%d%d",&I[i].x,&I[i].y);
		}
		sort(I,I+n,cmp);
		int ans = 1,lastX = I[0].x;
		for(int i = 1;i <n;i++){
			if(I[i].y <= lastX){
				lastX = I[i].x;
				ans++;
			}
		}
		printf("%d\n",ans);
	}
	return 0;
}