题目13：剩下的树

#include <stdio.h>#include <stdlib.h>int road[10001]={0};void removetree(int begin,int end){int i;for(i=begin;i<=end;i++){if(road[i]==1)road[i]=0;}}int main(){int l,n;while(scanf("%d%d",&l,&n)!=EOF){int i,j,k;int count;count=0;for(i=0;i<10001;i++){road[i]=1;}for(j=0;j<n;j++){int begin,end;scanf("%d%d",&begin,&end);removetree(begin,end);}for(k=0;k<=l;k++){if(road[k]==1)count++;}printf("%d\n",count);}return 0;}