CSU Scientific Conference

贪心：

#include<stdio.h>#include<stdlib.h>#define MAXN 100000 + 100int Ts[MAXN], Te[MAXN], r[MAXN], n, num;int cmp(const void *_p, const void *_q){    int *p = (int *)_p;    int *q = (int *)_q;    return Te[*p] - Te[*q];}void init(){    while(~scanf("%d",&n))    {        for(int i = 0; i < n; i ++)        {            scanf("%d%d",&Ts[i],&Te[i]);            r[i] = i;        }        qsort(r,n,sizeof(r[0]),cmp);        num = 1;        int t = 0;        for(int i = 1; i < n; i ++)        {            if(Ts[r[i]]>Te[r[t]])             {                num ++;                t = i;            }        }        printf("%d\n",num);    }}int main(){    init();    return 0;}