bzoj3192 [JLOI2013]删除物品

　　用数组表示两个栈，将两个栈的栈顶并在一起，用树状数组维护一下操作即可。

　　代码

 #include<cstdio>
 #include<algorithm>
 #include<map>
 #define lb(x) (x&-x)
 using namespace std;
 const int N = ;
 int n,m,i,id[N],a[N],b[N],c[N],top,tot;
 long long ans;
 map<int,int> ma;
 void cc(int x,int w)
 {
     while (x<=n+m)
     {
         c[x]+=w;
         x+=lb(x);
     }
 }
 int sum(int x)
 {
     int ans=;
     while (x)
     {
         ans+=c[x];
         x-=lb(x);
     }
     return ans;
 }
 int main()
 {
     scanf("%d%d",&n,&m);
     for (i=;i<=n;i++)
     scanf("%d",&a[i]),b[i]=a[i];
     for (i=n+;i<=n+m;i++)
     scanf("%d",&a[i]),b[i]=a[i];
     sort(b+,b++m+n);
     for (i=;i<=n+m;i++)
     if (ma[b[i]]==) ma[b[i]]=++tot;
     for (i=;i<=n+m;i++) a[i]=ma[a[i]];
     for (i=;i<=n;i++)
         id[a[i]]=n-i+;
     for (i=;i<=m;i++)
         id[a[n+i]]=n+i;

     for (i=;i<=n+m;i++) cc(i,);

     top=n;
     for (i=n+m;i>=;i--)
     {
         if (id[i]<=top)
         {
         ans+=sum(top)-sum(id[i]);
         top=id[i];
         }
         else
         {
         ans+=sum(id[i]-)-sum(top);
         top=id[i];
         }
         cc(id[i],-);
     }
     printf("%lld\n",ans);
 }