cf 755D. PolandBall and Polygon

题意：把一个多边形往里面连对角线，然后问每次添加多边形被划分为几个部分

产生的部分就是新加对角线与原有对角线相交条数+1，用线段树（大雾）维护一下。

 #include<bits/stdc++.h>
 #define LL long long
 #define N 100005
 #define lowbit(x) x&(-x)
 using namespace std;
 inline LL ra()
 {
     LL x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 LL n,k;
 struct node{
     LL tag,sum,l,r;
 }t[N<<];
 LL T,ans=;
 void build(LL k, LL l, LL r)
 {
     t[k].l=l; t[k].r=r;
     if (l==r) return;
     LL mid=l+r>>;
     build(k<<,l,mid); build(k<<|,mid+,r);
 }
 void update(LL k)
 {
     t[k].sum=t[k<<].sum+t[k<<|].sum;
 }
 void pushdown(LL k)
 {
     LL tmp=t[k].tag; t[k].tag=;
     t[k<<].tag+=tmp; t[k<<|].tag+=tmp;
     t[k<<].sum+=(t[k<<].r-t[k<<].l+)*tmp;
     t[k<<|].sum+=(t[k<<|].r-t[k<<|].l+)*tmp;
 }
 void change(LL k, LL x, LL y, LL val)
 {
     if (x>y || y>n) return;
     LL l=t[k].l,r=t[k].r;
     if (l==x && y==r)
     {
         t[k].tag+=val;
         t[k].sum+=(r-l+)*val;
         return;
     }
     if (t[k].tag) pushdown(k);
     LL mid=l+r>>;
     if (y<=mid) change(k<<,x,y,val);
     else if (x>mid) change(k<<|,x,y,val);
     else{
         change(k<<,x,mid,val);
         change(k<<|,mid+,y,val);
     }
     update(k);
 }
 LL ask(LL k, LL x, LL y)
 {
     if (x>y || y>n) return ;
     LL l=t[k].l,r=t[k].r;
     if (x==l && y==r) return t[k].sum;
     if (t[k].tag) pushdown(k);
     LL mid=l+r>>;
     if (y<=mid) return ask(k<<,x,y);
     else if (x>mid) return ask(k<<|,x,y);
     else return ask(k<<,x,mid)+ask(k<<|,mid+,y);
 }
 int main()
 {
     LL last=,aim;
     T=n=ra(); k=ra();
     if (k>n/) k=n-k;
     build(,,n);
     while (T--)
     {
         LL aim=(last+k-)%n+;
         if (aim>last)
         {
             ans+=ask(,last+,aim-)+;
             change(,last,last,);
             change(,aim,aim,);
         }
         else
         {
             ans+=ask(,last+,n)+ask(,,aim-)+;
             change(,last,last,); change(,aim,aim,);
         }
         last=aim;
         printf("%I64d ",ans);
     //    cout<<ask(2); system("pause");
     }
     return ;
 }