区间重叠的合并模板

    struct Day
    {
        ll l,r;
    } day[N];
    int cnt=0;
    for(int i=1; i
    {
        if(day[i].l<=day[cnt].r+1)
            day[cnt].r=max(day[cnt].r,day[i].r);
        else
        {
            day[++cnt].l=day[i].l;
            day[cnt].r=day[i].r;
        }
    }