spoj8406

题解：

二分+树状数组

记录以下i在当前拍第几

代码：

#include<bits/stdc++.h>
using namespace std;
const int N=;
int a[N],f1[N],f2[N],n,m,x,y,num[N];
int js(int x)
{
    int ans=;
    for (;x;x-=x&-x)ans+=num[x];
    return ans;
}
void inster(int x,int y)
{
    for (;x<=n;x+=x&-x)num[x]+=y;
}
int cmp(int x,int y)
{
    return a[x]<a[y];
}
int main()
{
    scanf("%d%d",&n,&m);
    for (int i=;i<=n;i++)scanf("%d",&a[i]),f1[i]=f2[i]=i;
    sort(f1+,f1+n+,cmp);
    for (int i=;i<=n;i++)f2[f1[i]]=i;
    for (int i=;i<=n;i++)inster(i,a[f1[i]]-a[f1[i-]]);
    while (m--)
     {
         scanf("%d%d",&x,&y);
         if (x==)
          {
             if (js(n)<y){puts("");continue;}
              int l=,r=n;
              while (l<r)
               {
                   int mid=(l+r)/;
                   if (y>js(mid))l=mid+;
                   else r=mid;
               }
              printf("%d\n",n-l+);
          }
         if (x==)
         {
             if (js(n)<y)continue;
              int l=,r=n;
              while (l<r)
               {
                   int mid=(l+r)/;
                   if (y>js(mid))l=mid+;
                   else r=mid;
               }
              inster(l,-);
         }
         if (x==)
         {
             int l=,r=n,k=js(f2[y]);
             while (l<r)
              {
                  int mid=(l+r+)/;
                  if (k<js(mid))r=mid-;
                  else l=mid;
              }
             swap(f1[f2[y]],f1[l]);
            swap(f2[f1[f2[y]]],f2[f1[l]]);
            inster(l,);
            inster(l+,-);
         }
     }
}