> 
> /*
> 算法：离散化+暴力
> 	首先输入所有线段，将它的起点终点排序，得到离散化的点
> 	将离散化的点从头到尾走一遍，得到每条线段对应的离散点编号
> 	对每条线段，更新离散点的上的颜色
> */
> 
> #include <stdio.h>
> #include <memory.h>
> #include <stdlib.h>
> #define MAX 10020
> 
> struct poster{
> 	int start;
> 	int end;
> }l[MAX];
> 
> int posters[MAX][2];
> 
> struct point{ //离散点
> 	int pos;
> 	int colour;  //对应的
> }p[2*MAX];
> 
> int cmp(const void* a, const void* b){
> 	struct point*p = (struct point*)a;
> 	struct point*q = (struct point*)b;
> 	return p->pos - q->pos;
> }
> 
> int n;
> int colour[2*MAX]; //离散点的颜色
> int used[MAX]; //出现过的海报颜色
> 
> int main(){
> 	int out;
> 	scanf("%d",&out);
> 	while(out--){
> 		memset(l,0,sizeof(l));
> 		memset(posters,0,sizeof(posters));
> 		memset(colour, -1, sizeof(colour));
> 		memset(used,0,sizeof(used));
> 
> 		scanf("%d",&n);
> 		int i,counter=0;
> 		for(i=0; i<n; i++){
> 			scanf("%d%d",&posters[i][0],&posters[i][1]);
> 			p[counter].pos = posters[i][0];
> 			p[counter++].colour = -i;
> 			p[counter].pos = posters[i][1];
> 			p[counter++].colour = i;
> 		}
> 		//离散化
> 		qsort(p,counter,sizeof(point),cmp);
> 		int real_point=0;
> 		int last_pos = -1; //与所有点都不同
> 		for(i=0; i<counter; i++){
> 			if(last_pos != p[i].pos) real_point++, last_pos = p[i].pos;
> 			if(p[i].colour < 0 ) l[-p[i].colour].start = real_point-1; //离散点的编号
> 			else l[p[i].colour].end = real_point-1;
> 		}
> 
> 		for(i=0; i<n; i++)
> 			for(int j=l[i].start; j<= l[i].end; j++)
> 				colour[j] = i;
> 		int ans=0;
> 		for(i=0; i<real_point; i++)
> 			if(!used[colour[i]]) ans++,used[colour[i]] = true;
> 
> 			printf("%d\n",ans);
> 
> 	}
> 	return 0;
> }
thank you