感觉数据范围蛮小的,于是直接上数组了
include [HTML_REMOVED]
include [HTML_REMOVED]
int a[10001];
int main(){
int l,n;
scanf(“%d%d”,&l,&n);
int start,end;
while(n–){
scanf(“%d%d”,&start,&end);
for(int i=start;i<=end;i){
a[i]=1;
}
}
int cnt=0;
for(int i=0;i<=l;i){
if(a[i]==0) cnt++;
}
printf(“%d”,cnt);
return 0;
}