poj 2037 今年暑假不AC

简单贪心，选择不相交区间：

 1 #include<stdio.h>

 2 #include<stdlib.h>

 3 

 4 int n, s[25], e[25], r[25];

 5 

 6 int cmp(const void *_p, const void *_q)

 7 {

 8     int *p = (int *)_p;

 9     int *q = (int *)_q;

10     return e[*p]-e[*q];

11 }

12 

13 int main()

14 {

15     while(scanf("%d",&n))

16     {

17         if(n == 0) break;

18         for(int i = 0; i < n; i ++)

19         {

20             scanf("%d%d",&s[i],&e[i]);

21             r[i] = i;        

22         }

23         qsort(r,n,sizeof(r[0]),cmp);

24         int ans = -1, count = 0;

25         for(int i = 0; i < n; i ++)

26             if(s[r[i]] >= ans){ans = e[r[i]]; count ++;}

27         printf("%d\n",count);

28     }    

29     return 0;

30 }