路边的树

#include <stdio.h>void main(){int L,i,j,n,begin,end,count;int trees[10001];//路最大长度为10000。树的个数多1scanf("%d%d",&L,&n);for(i=0;i<=L;i++)//初始化标志为1{trees[i]=1;}for (i=0;i<n;i++){scanf("%d%d",&begin,&end);for (j=begin;j<=end;j++){trees[j]=0;}}for(count=0,i=0;i<=L;i++){if(trees[i]){count++;}}printf("%d\n",count);}